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UBC Theses and Dissertations

A study of submerged gas jets injected horizontally into liquid metals Oryall, Gregory N. 1975

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A STUDY OF SUBMERGED GAS JETS INJECTED HORIZONTALLY INTO LIQUID METALS by Gregory N. O r y a l l A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF APPLIED SCIENCE i n t h e Department of METALLURGY  We a c c e p t t h i s t h e s i s as c o n f o r m i n g t o standard required  from c a n d i d a t e f o r t  degree o f MASTER OF APPLIED SCIENCE  THE UNIVERSITY OF BRITISH COLUMBIA J u l y , 1975.  In p r e s e n t i n g t h i s  thesis  an advanced degree at the L i b r a r y s h a l l I  f u r t h e r agree  in p a r t i a l  fulfilment of  the requirements f o r  the U n i v e r s i t y of B r i t i s h Columbia,  make it  freely available  that permission  for  I agree  r e f e r e n c e and  for e x t e n s i v e c o p y i n g o f  this  that  study. thesis  f o r s c h o l a r l y purposes may be granted by the Head o f my Department or by h i s of  this  representatives. thesis  for  It  i s understood that c o p y i n g or p u b l i c a t i o n  f i n a n c i a l gain s h a l l  w r i t ten pe rm i ss ion .  Department of  ftlBfft  it U  The U n i v e r s i t y of B r i t i s h 2075 Wesbrook P l a c e V a n c o u v e r , Canada V6T 1W5  jl&  Columbia  not  be allowed without my  ii ABSTRACT  The p h y s i c a l c h a r a c t e r i s t i c s o f a submerged a i r j e t i n j e c t e d h o r i z o n t a l l y i n t o a bath o f mercury were s t u d i e d under i s o t h e r m a l , n o n - r e a c t i v e c o n d i t i o n s f o r n o z z l e  diameters  o f 0.325 cm. and 0.476 cm. and over a range o f m o d i f i e d Froude numbers w i t h v a l u e s from 20 t o 300.  A specially-  designed e l e c t r o - r e s i s t i v i t y probe a l l o w e d t h e measurement of gas volume f r a c t i o n and bubble frequency a t a l l p o i n t s w i t h i n the j e t .  The d i s t r i b u t i o n o f these v a l u e s has been  expressed as a s e r i e s o f contour maps on a of o r t h o g o n a l p l a n e s .  grid-sequence  J e t cone a n g l e , d i a m e t e r , and pene-  t r a t i o n d i s t a n c e s were measured and compared t o v a l u e s obt a i n e d under s i m i l a r c o n d i t i o n s i n t h e a i r - w a t e r system.  The events o c c u r r i n g i n t h e development o f a submerged gas j e t i n a l i q u i d were s t u d i e d by means o f h i g h speed c i n e m a t i c photography i n t h e a i r - w a t e r system. Mathematical  models p r e d i c t i n g j e t b e h a v i o u r have been  examined i n t h e a i r - m e r c u r y system and t h e e x t r a p o l a t i o n of e x p e r i m e n t a l r e s u l t s t o i n d u s t r i a l copper c o n v e r t i n g and s t e e l m a k i n g o p e r a t i o n s has been d i s c u s s e d .  iii TABLE OF CONTENTS Page ABSTRACT  i i  TABLE OF CONTENTS  • i i i  LIST OF FIGURES  v  i  LIST OF TABLES  i x i  LIST OF SYMBOLS  . . .  x  i  i  ACKNOWLEDGEMENT 1.  INTRODUCTION  1  1.1 Submerged Gas J e t s i n M e t a l l u r g i c a l Processes  1  1.1.1  The Copper I n d u s t r y  1  1.1.2  The I r o n and S t e e l I n d u s t r y . .  3  1.1.3  Other M e t a l I n d u s t r i e s  5  ....  1.2 T e c h n i c a l Background and P r e v i o u s Studies 1.2.1 1.2.2 1.2.3  1.2.4  The Formation in a liquid  7  o f Gas Bubbles 7  Shape and R i s e V e l o c i t y o f bubbles  11  Homogeneous J e t s  14  1.2.3.1  Behaviour o f Homogeneous j e t s  14  1.2.3.2  J e t Cone A n g l e . . . .  19  1.2.3.3  E f f e c t of Density D i f f e r e n c e s upon j e t trajectory  21  Gas J e t s i n L i q u i d s Heterogeneous J e t s  22  1.2.4.1  General Considerations  22  1.2.4.2  P r e v i o u s Work  23  ....  OVERVIEW OF THE PRESENT WORK  . .  APPARATUS AND PROCEDURES . 1 A i r J e t s i n j e c t e d H o r i z o n t a l l y i n t o mercury 3.1.1 P h y s i c a l A p p a r a t u s  3.1.2  3.1.1.1  The A i r D e l i v e r y System  . .  3.1.1.2  The Mercury Tank  3.1.1.3  The E l e c t r o r e s i s t i v i t y Probe  E l e c t r o n i c Apparatus 3.1.2.1  The I n t e g r a t o r  3.1.2.2  The Counter  3.1.2.3  The Timer  3.1.3  General Operating Procedure  3.1.4  V e l o c i t y Measurements  3.1.5  Measurements o f Mercury B a c k f l o w i n t o the tuyere . . . .  3.1.6  E v a l u a t i o n o f Equipment performance .  3.1.7  S t a t i s t i c a l Evaluation.of data reproduceability  .2  A i r J e t s i n j e c t e d H o r i z o n t a l l y i n t o water  3.2.1 P h y s i c a l A p p a r a t u s 3.2.2  E l a p s e d - t i m e photography  3.2.3  J e t D e t e r m i n a t i o n by e l e c t r o r e s i s t i v i t y probe . . . . .  3.2.4  High-speed c i n e m a t i c photography  3.2.5  S l u g f l o w measurements  . .  V  Page 4.  RESULTS 4.1  ,  63  Submerged H o r i z o n t a l A i r J e t s i n Mercury 4.1.1  V o l u m e t r i c gas d i s t r i b u t i o n w i t h i n the j e t . .  57  4.1.2  Bubble f r e q u e n c y d i s t r i b u t i o n  ...  4.1.3  V e l o c i t y measurements  86  4.1.4  Measurements o f mercury b a c k f l o w i n t o the tuyere  86  4.2 Submerged H o r i z o n t a l A i r J e t s i n Water  5.  63  4.2.1  E l a p s e d - t i m e photography  4.2.2  T r a j e c t o r y d e t e r m i n a t i o n by  71  87 88  probe and photography  90  4.2.3  O b s e r v a t i o n s of J e t p u l s a t i o n . . .  91  4.2.4  O b s e r v a t i o n s of s l u g g i n g b e h a v i o u r .  96  DISCUSSION  99  5.1  G e n e r a l D e s c r i p t i o n of a H o r i z o n t a l l y I n j e c t e d Gas J e t i n Mercury .  5.2  Cone Angle  100  5.3  J e t Diameter  107  5.4  Jet Trajectory  109  5.5  J e t Penetration  114  5.6  O r i g i n s of J e t Behaviour  119  5.6.1  Jet Pulsations  119  5.6.2  P h y s i c a l P r o p e r t i e s of the L i q u i d .  120  99  vl Page S.7  Extension  to industrial  121  5.7.1  P h y s i c a l p r o p e r t i e s o f the l i q u i d  5.7.2  Phenomenological comparison 5.7.2.1  5.7.2.2 5.7.2.3  6.  systems  CONCLUSION. Summary  6.2  Suggested Future  121  . . . .  123  Tuyere p l u g g i n g i n t h e ladle desulphurization of steel. . . . . . . . . . .  123  Tuyere e r o s i o n d u r i n g copper c o n v e r t i n g .....  125  Back-wall e r o s i o n i n a copper c o n v e r t e r . . . . .  126  . . . . . . . .  6.1  .  . . . . . . . ... • •  127 127  Work  128  APPENDIX I  130  APPENDIX I I .  133  APPENDIX I I I  135  APPENDIX IV  172  REFERENCES  210  L i s t of Figures Page  F i g u r e 1.  V a r i a t i o n o f mean bubble d i a m e t e r w i t h o r i f i c e d i a m e t e r and Reynolds number f o r t h e a i r - w a t e r system. From L e i b s o n e t a l ( 3 7 ) .  10  Schematic diagrams o f j e t f l o w showing p o t e n t i a l flow core (shaded area) and v e l o c i t y p r o f i l e s a t v a r i o u s d i s t a n c e s from o r i f i c e . From S z e k e l y and Themelis ( 8 5 ) .  15  J e t velocity p r o f i l e s i n r a d i a l sections at d i f f e r e n t d i s t a n c e s (x) from o r i f i c e . From S z e k e l y and Themelis ( 8 5 ) .  17  F i g u r e 4.  Dimensionless v e l o c i t y p r o f i l e i n a plane j e t . From Abramovich (61) .  18  F i g u r e 5. 5.  Schematic o f a p p a r a t u s employed air-mercury j e t s .  34  F i g u r e 6.  Schematic o f mercury t a n k .  F i g u r e 7.  Photographs o f t h e c o n v e r t e r - t y p e tank and a n c i l l a r y 38 a p p a r a t u s used i n t h e a i r - m e r c u r y t e s t s .  F i g u r e 8.  Schematic o f e l e c t r o r e s i s t i v i t y probe.  F i g u r e 9.  Schematic o f e l e c t r o n i c a p p a r a t u s employed study o f a i r - m e r c u r y j e t s .  F i g u r e 2.  F i g u r e 3.  i n the study of  37  40 i n the  F i g u r e 10. S e c t i o n a l diagram o f t e f l o n n o z z l e used i n t h e  d e t e r m i n a t i o n o f mercury b a c k f l o w .  F i g u r e 11. A V o l t a g e p u l s e r e c o r d e d a t a t r a c e speed o f 2 ms.  / d i v i s i o n , or  500 cm./s.  F i g u r e 12. F i v e f a s t v o l t a g e p u l s e s viewed a t a t r a c e  o f 1 ms. / d i v i s i o n , o r 1000 cm/s.  speed  42 47 49 50  F i g u r e 13. O s c i l l o s c o p e t r a c e s showing v o l t a g e p u l s e s caused  by b u b b l e s p a s s i n g t h e p r o b e - t i p , w i t h c o r r e s p o n d i n g 52 c o u n t e r - b l i p s above.  F i g u r e 14. S t i l l  photograph o f an a i r j e t i n water showing s l u g s .  F i g u r e 15. F i g u r e 15a  (Re= 38,400)  Photograph o f a "catch-box" used i n t h e measurement of s l u g f l o w . I l l u s t r a t i o n o f catch-box placement i n t h e measurement o f t h e s l u g - f l o w .  5  ^ 6 0  61  vili Page F i g u r e 16.  Probe t r a c e t h r o u g h an a i r - m e r c u r y j e t showing gas d i s t r i b u t i o n p r o f i l e .  64  Probe t r a c e t h r o u g h an a i r - m e r c u r y j e t showing bubble f r e q u e n c y p r o f i l e .  65  F i g u r e 18.  I l l u s t r a t i o n o f g r i d - p l a n e placement c l a t u r e as used i n c o n t o u r mapping.  68  F i g u r e 19.  Contour map o f volume p e r c e n t a i r f o r t h e p l a n e 2 = 1.3 o f r u n HG1.  69  Contour map o f volume p e r c e n t a i r f o r t h e p l a n e X = 0 o f r u n HG1.  70  Contour map o f volume p e r c e n t a i r f o r t h e p l a n e & = 1.3 of r u n HG2.  72  Contour map of volume p e r c e n t a i r f o r t h e p l a n e X = 0 o f r u n HG2.  73  Contour map o f volume p e r c e n t a i r f o r t h e p l a n e 2 = 1.3 o f r u n HG 3.  74  Contour map o f volume p e r c e n t a i r f o r t h e p l a n e X = 0 o f r u n HG 3.  75  Contour map o f volume p e r c e n t a i r f o r t h e p l a n e S = 1.3 o f r u n HG 4 .  76  Contour map o f volume p e r c e n t a i r f o r t h e p l a n e X = 0 o f r u n HG 4.  77  Contour map o f bubble f r e q u e n c y f o r t h e p l a n e a = 1.3 of r u n HG 1.  78  Contour map o f bubble f r e q u e n c y f o r t h e p l a n e X = 0 o f r u n HG 1.  79  Contour map o f bubble f r e q u e n c y f o r t h e p l a n e a = 1.3 o f r u n HG 2.  80  Contour map o f bubble f r e q u e n c y f o r t h e p l a n e X = 0 o f r u n HG 2.  81  F i g u r e 17.  F i g u r e 20. F i g u r e 21. F i g u r e 22. F i g u r e 23. F i g u r e 24. F i g u r e 25. F i g u r e 26. F i g u r e 27. F i g u r e 28. F i g u r e 29. F i g u r e 30.  and nomen-  F i g u r e 31.  Contour map o f bubble f r e q u e n c y f o r t h e p l a n e 3 = 1.3 o f r u n HG 3.  F i g u r e 32.  Contour map o f bubble f r e q u e n c y f o r t h e p l a n e X = 0 o f r u n HG3.  82  83  ix Page F i g u r e 33.  Contour map o f b u b b l e f r e q u e n c y f o r t h e p l a n e 2 = 1.3 o f r u n HG4.  84  F i g u r e 34.  Contour map o f b u b b l e f r e q u e n c y f o r t h e p l a n e X = 0 o f r u n HG 4.  85  F i g u r e 35.  E l a p s e d - t i m e photograph o f a submerged a i r j e t i n w a t e r . Two p i c t u r e s of t h e same photograph p r i n t e d under d i f f e r e n t c o n d i t i o n s t o show t h e extent of p o s s i b l e v a r i a t i o n i n envelope s i z e .  89  F i g u r e 36.  Probe t r a c e t h r o u g h an a i r - w a t e r j e t .  92  F i g u r e 37.  The e n v e l o p e and as d e t e r m i n e d by N' F r = 1500. The e n v e l o p e and as d e t e r m i n e d by N' = 6700.  F i g u r e 38.  t r a j e c t o r y o f an a i r - w a t e r j e t photography and probe.  93  t r a j e c t o r y o f an a i r - w a t e r j e t photography and probe.  94  p r  F i g u r e 39.  A sequence o f frames showing one complete p u l s a t i o n o f an a i r j e t i n w a t e r .  95  F i g u r e 40.  A sequence o f frames showing t h e development o f a slug.  97  F i g u r e 41.  I l l u s t r a t i o n o f t h e f l o w p a t t e r n i n t h e c a t c h box. 98  F i g u r e 42.  T i m e - l a p s e photograph o f an a i r - w a t e r j e t i n t h e c y l i n d r i c a l v e s s e l used d u r i n g t h e a i r - m e r c u r y t e s t s . The cone a n g l e i s 20°. 103  F i g u r e 43.  J e t w i d t h v s . t u y e r e submergence. T r a v e r s e t a k e n a t 0.3 cm. above t h e t u y e r e f o r Run HG4. 105  F i g u r e 44.  J e t w i d t h v s . t u y e r e submergence. T r a v e r s e t a k e n 106 a t 1.3 cm. above t h e t u y e r e f o r Run HG 4.  F i g u r e 45,  J e t diameter v s . d i s t a n c e along t r a j e c t o r y .  108  F i g u r e 46.  Comparison o f e x p e r i m e n t a l and t h e o r e t i c a l j e t t r a j e c t o r i e s f o r Run HG 1.  110  F i g u r e 47,  Comparison o f e x p e r i m e n t a l and t h e o r e t i c a l j e t t r a j e c t o r i e s f o r Run HG 2.  111  F i g u r e 48,  Comparison o f e x p e r i m e n t a l and t h e o r e t i c a l j e t t r a j e c t o r i e s f o r Run HG 3.  112  X  Page F i g u r e 49.  Comparison of e x p e r i m e n t a l and t h e o r e t i c a l j e t t r a j e c t o r i e s f o r Run HG 4.  113  F i g u r e 50.  Photo i l l u s t r a t i n g l a n c e p l u g g i n g due t o backflow of l i q u i d s t e e l i n t o a lance. Courtesy of Wood, e t a l ( 8 6 ) .  124  C i r c u i t diagram o f t h e i n t e g r a t o r used i n t h e a i r - m e r c u r y e x p e r i m e n t s t o measure gas volume fraction.  131  C i r c u i t diagram o f t h e b o u n c e l e s s s w i t c h and power s u p p l y used i n t h e a i r - m e r c u r y e x p e r i m e n t s .  132  F i g u r e 51.  F i g u r e 52.  xi  L i s t of Tables Page TABLE I .  S t a t i s t i c a l E v a l u a t i o n o f Sampling Accuracy  54  TABLE I I .  Operating c o n d i t i o n s t e s t e d i n the a i r - m e r c u r y system.  66  TABLE I I I . J e t cone a n g l e s measured a t a h o r i z o n t a l d i s t a n c e o f 0.5 cm. from t h e n o z z l e .  102  TABLE IV.  Experimental j e t penetration distances a t a v e r t i c a l d i s t a n c e above t h e n o z z l e of 6.3 cm. 115  TABLE V.  Comparison o f e x p e r i m e n t a l and theoretical j e t penetration distances a t a v e r t i c a l d i s t a n c e above t h e n o z z l e o f 6.3 cm.  TABLE V I .  117  Comparative p h y s i c a l p r o p e r t i e s o f a i r , w a t e r , mercury, l i q u i d copper, and l i q u i d iron or s t e e l . 122  Acknowledgement I would l i k e t o thank my  research d i r e c t o r ,  Dr. K e i t h Brimacombe, f o r h i s a s s i s t a n c e and throughout the c o u r s e of t h i s r e s e a r c h  guidance  project.  I would  a l s o l i k e t o thank E. K l a s s e n and D. Brandys f o r t h e i r c o n t i n u a l work i n the d e s i g n and c o n s t r u c t i o n o f  the  e l e c t r o n i c a p p a r a t u s used i n t h i s p r o j e c t .  In a d d i t i o n , g r a t i t u d e i s e x p r e s s e d t o Noranda Group who e n t i r e research Fellowship.  the  supplied f i n a n c i a l support during  this  p r o j e c t t h r o u g h a Noranda Graduate Research  1  CHAPTER 1 INTRODUCTION  1.1  Submerged Gas J e t s i n M e t a l l u r g i c a l P r o c e s s e s  The  a r t o f b l o w i n g submerged gas j e t s i n t o l i q u i d  m e t a l s i n o r d e r t o o b t a i n h i g h mass t r a n s f e r r a t e s has been s u c c e s s f u l l y a p p l i e d t o many i m p o r t a n t m e t a l l u r g i c a l processes.  Copper matte c o n v e r t i n g  i s well established  i n m e t a l l u r g i c a l i n d u s t r y and i s t h e o b v i o u s example of t h i s a p p l i c a t i o n .  However, t h e l i s t o f such p r o c e s s e s  i s l a r g e and, i n r e c e n t y e a r s , has been growing q u i c k l y t o i n c l u d e t h e gaseous d e o x i d a t i o n o f copper, t h e new c o n t i n u o u s copper s m e l t i n g p r o c e s s d e v e l o p e d by Noranda, many v a r i a t i o n s on bottom-blown s t e e l m a k i n g  processes,  as w e l l as l a d l e d e g a s s i n g and d e s u l p h u r i z a t i o n .  Several  of t h e more prominent p r o c e s s a p p l i c a t i o n s w i l l now be discussed gas  i n terms o f t h e i r u t i l i z a t i o n o f submerged  jets.  1.1.1  The Copper  The  Industry  pyrometallurgical production  o f copper commonly  i n v o l v e s t h e p r o c e s s o f " c o n v e r t i n g " , which t r e a t s t h e matte r e s u l t i n g from p r e v i o u s  smelting operations t o  produce a p r o d u c t known as b l i s t e r c o p p e r , c o n t a i n i n g  2  about 99% copper and s m a l l amounts o f base m e t a l i m p u r i t i e s . S i n c e the t u r n o f the c e n t u r y , t h i s p r o c e s s has almost u n i v e r s a l l y been conducted i n a P e i r c e - S m i t h c o n v e r t e r , a c y l i n d r i c a l v e s s e l t y p i c a l l y 30 f e e t l o n g by 13 f e e t i n diameter.  A bank of h o r i z o n t a l t u y e r e s i s l o c a t e d  a l o n g t h e l e n g t h o f t h e c o n v e r t e r below t h e l e v e l o f the l i q u i d s u r f a c e .  The i r o n and s u l p h u r a r e o x i d i z e d  by b l o w i n g a i r through the m o l t e n matte;  sulphur i s  removed i n t h e gases as SC^ w h i l e t h e i r o n i s o x i d i z e d and s l a g g e d o f f . In March, 197 3, t h e Noranda P r o c e s s C o n t i n u o u s S m e l t e r (1,2) began f u l l - s c a l e o p e r a t i o n t o s m e l t 800 t o n s a day of s u l p h i d e copper c o n c e n t r a t e d i r e c t l y t o m e t a l l i c copper, combining b o t h t h e s m e l t i n g and conv e r t i n g f u n c t i o n s i n a s i n g l e v e s s e l under c o n t i n u o u s , dynamic e q u i l i b r i u m .  E f f i c i e n t h e a t and mass t r a n s f e r  are o b t a i n e d by b l o w i n g a i r , o r o x y g e n - e n r i c h e d a i r , through a s e r i e s o f submerged h o r i z o n t a l t u y e r e s , t h u s m a i n t a i n i n g a p o r t i o n o f the r e a c t o r b a t h i n a h i g h l y turbulent state. The b l i s t e r copper produced i n a copper c o n v e r t e r or by the Noranda P r o c e s s i s s t i l l u s u a l l y t o o impure f o r d i r e c t use and must be r e f i n e d t o produce grades o f copper.  commercial  T h i s r e f i n i n g procedure a g a i n i n v o l v e s  3  t h e use o f submerged gas j e t s .  I m p u r i t i e s such as  Fe, Sn, Sb, Zn and some o f t h e N i , Co, and Pb i n t h e molten b l i s t e r copper a r e o x i d i z e d i n an anode f u r n a c e by means o f submerged i n j e c t i o n o f a i r o r o x y g e n - e n r i c h e d air.  The i m p u r i t y - m e t a l o x i d e s a r e e i t h e r  o r skimmed o f f as a s l a g .  volatilized  The r e s u l t i n g o x y g e n - r i c h  copper  i s then t r e a t e d by an o p e r a t i o n known as p o l i n g , i n which wooden p o l e s a r e t h r u s t i n t o t h e b a t h and burn t o e v o l v e r e d u c i n g gases which r e a c t w i t h t h e oxygen i n t h e copper. C u r r e n t l y , t h e p o l i n g procedure  i s being replaced i n  many p l a n t s by t h e d i r e c t submerged i n j e c t i o n o f v a r i o u s r e d u c i n g gases (3,4). The r e d u c i n g gas, which i s i n t r o duced through t h e e x i s t i n g n o z z l e s f o l l o w i n g t h e o x i d i z i n g blow, may be n a t u r a l gas (5,6,7,8), propane ( 9 ) , ammonia (10), o r p u l v e r i z e d c o a l blown i n a c a r r i e r gas ( 1 1 ) .  1.1.2  The I r o n and S t e e l I n d u s t r y  Submerged gas i n j e c t i o n was f i r s t used c o m m e r c i a l l y i n t h e p r o d u c t i o n o f s t e e l as e a r l y as 1860 when t h e Bessemer bottom-blown a c i d p r o c e s s f o r c o n v e r t i n g b l a s t f u r n a c e p i g i r o n i n t o s t e e l became o p e r a t i o n a l i n S h e f f i e l d , England.  The p r o c e s s o x i d i z e d and removed major i m p u r i t i e s  from l i q u i d p i g i r o n by b l o w i n g a c o l d a i r j e t v e r t i c a l l y upwards through t h e molten m e t a l b a t h .  I n 1879 t h e Thomas  p r o c e s s , i n v o l v i n g t h e same b l o w i n g c h a r a c t e r i s t i c s as  4  the Bessemer p r o c e s s , was p a t e n t e d and e x t e n s i v e l y adopted i n c o n t i n e n t a l Europe.  The improvement, i n t h i s  case,  c o n s i s t e d o f t h e use o f a b a s i c l i n i n g and f l u x w h i c h a l l o w e d t h e s m e l t i n g o f high-phosphorous o r e s common t o many r e g i o n s o f Europe.  Both t h e Thomas and Bessemer  p r o c e s s e s , however, were soon r e p l a c e d by open-hearth s t e e l m a k i n g and t h e BOF, whereupon t h e use o f submerged gas j e t s i n t h e r e f i n i n g o f s t e e l was l a r g e l y i g n o r e d u n t i l more r e c e n t t i m e s . Bottom-blown s t e e l m a k i n g , however, i s today making a dramatic r e v i v a l  (12,13,14) due l a r g e l y t o t h e d e v e l o p -  ment o f a c o n c e n t r i c t u y e r e which a l l o w s i n j e c t e d oxygen, d e s i r a b l e f o r f a s t r e a c t i o n t i m e s , t o be s h i e l d e d w i t h another g a s , thus e l i m i n a t i n g e x t r e m e l y h i g h a d j a c e n t t o t h e bottom r e f r a c t o r i e s . process  temperatures  The OBM o r Q-BOP  (15) i n j e c t s oxygen s h i e l d e d w i t h propane o r any  o t h e r hydrocarbon  g a s , whereas t h e LWS p r o c e s s  the oxygen w i t h steam o r f u e l o i l .  shields  Both t h e OBM and  LWS  v e s s e l s a r e s i m i l a r i n c o n f i g u r a t i o n and o p e r a t i o n t o a Bessemer c o n v e r t e r .  The Submerged I n j e c t i o n  Process  (SIP) i n j e c t s t h e gas n e a r - h o r i z o n t a l l y i n t o an openh e a r t h f u r n a c e t o a c c e l e r a t e normal open-hearth r e f i n i n g rates.  5  I n a d d i t i o n , two new p r o c e s s e s f o r s t a i n l e s s s t e e l p r o d u c t i o n , t h e AOD (16, 17) and CLU (18) p r o c e s s e s , are b o t h based on t h e submerged i n j e c t i o n o f gases i n t o a l i q u i d m e t a l b a t h , and argon l a d l e - d e g a s s i n g (19) and l a d l e d e s u l p h u r i z a t i o n (20) u t i l i z e submerged gas i n j e c t i o n t o e f f e c t mass and momentum t r a n s f e r i n l i q u i d  metals  outside the furnace.  1.1.3  Other M e t a l I n d u s t r i e s R e c e n t l y many companies have been l o o k i n g i n t o t h e  d i r e c t s m e l t i n g o f l e a d c o n c e n t r a t e s and s e v e r a l o f t h e r e s u l t i n g p r o c e s s e s a r e based on submerged gas i n j e c t i o n (21,22).  The S t . J o e M i n e r a l s Corp. has developed  a  P e i r c e - S m i t h type c o n v e r t e r f o r t h e submerged s m e l t i n g of l e a d c o n c e n t r a t e  (23) .  The Queneau-Schuhmann p r o c e s s  (24) p r o v i d e s c o n t i n u o u s autogenous c o n v e r s i o n o f s u l p h i d e o r e c o n c e n t r a t e s i n a s i n g l e v e s s e l by means o f submerged oxygen b l o w i n g , and c l a i m s a p p l i c a b i l i t y t o t h e t r e a t m e n t of many m e t a l s u l p h i d e s such as copper, n i c k e l , c o b a l t and l e a d .  Noranda has a l s o p a t e n t e d a p r o c e s s f o r c o n t i n -  uous l e a d s m e l t i n g which i s s i m i l a r t o t h e i r Noranda P r o c e s s f o r copper, mentioned e a r l i e r . In a d d i t i o n , t h e submerged s m e l t i n g o f t i n s l a g s i s c u r r e n t l y b e i n g examined (25) w i t h a view t o t h e  6  p o s s i b i l i t y o f t r e a t i n g lower-grade c o n c e n t r a t e s . I f one c o n s i d e r s as w e l l t h e many o p e r a t i o n s i n v o l v i n g g a s - s t i r r i n g , which u t i l i z e o n l y t h e momentum of t h e j e t , i t becomes apparent t h a t submerged gas i n j e c t i o n o f f e r s a wide v a r i e t y o f o p p o r t u n i t i e s t o enhance t h e t r a n s f e r o f h e a t , mass and momentum i n many metallurgical  operations.  7  1-2  T e c h n i c a l Background and P r e v i o u s  1.2.1  The Formation  Studies  o f Gas Bubbles i n a L i q u i d  There i s g e n e r a l agreement among i n v e s t i g a t o r s (2653) t h a t t h r e e d i s t i n c t regimes o f b u b b l e f o r m a t i o n may be i n d e n t i f i e d as a f u n c t i o n o f gas f l o w r a t e .  (i)  The s t a t i c regime:  of t h e o r d e r o f 1 ml/s.  A t v e r y low gas f l o w r a t e s ,  ( N . < 500), t h e frequency  o f bubble  Re  f o r m a t i o n i s p r o p o r t i o n a l t o t h e gas f l o w r a t e and t h e bubble s i z e i s almost c o n s t a n t .  The bubble frequency  below 100 b u b b l e s p e r minute.  i susually  At these v a n i s h i n g l y s m a l l  gas f l o w s t h e f o r m a t i o n o f a bubble may be d e s c r i b e d i n 4 3 terms o f a b a l a n c e between a buoyancy f o r c e ,  nR (p B  L  P (  _.)  and a s u r f a c e t e n s i o n f o r c e , 2 I T r a(cos -6H f ( % , whe r e : 0  R_, = r a d i u s o f t h e bubble a t t h e moment o f r e l e a s e p  hi  L  P  G  g r o f  = density of the l i q u i d = d e n s i t y o f t h e gas = gravitational acceleration  G  = radius of the o r i f i c e = surface tension of the l i q u i d  •0- = a n g l e o f c o n t a c t a t t h e t r i p l e i n t e r f a c e (—°-) = a shape f a c t o r w h i c h , f o r a sphere, has t h e v a l u e 1.  I f i t i s assumed t h a t t h e r e i s p e r f e c t w e t t i n g o f t h e o r i f i c e by t h e l i q u i d then <3- =F 0 and e q u a t i n g t h e two  g,  8  f o r c e s y i e l d s the bubble  size:  '  fc-V -  ]V3<1 1)  The b u b b l e d i a m e t e r i s t h e r e f o r e p r o p o r t i o n a l t o t h e cube r o o t o f t h e o r i f i c e d i a m e t e r b u t i s i n d e p e n d e n t o f the  gas f l o w r a t e . (ii)  The dynamic regime:  about 100 mL£. (500 < N_.  x\.e .  <  Up t o a gas f l o w o f  2100), i n v o l v i n g b u b b l e  f r e q u e n c i e s u s u a l l y g r e a t e r t h a n 500 b u b b l e s p e r m i n u t e , the  b u b b l e volume i n c r e a s e s w i t h gas f l o w r a t e w h i l e t h e  f r e q u e n c y o f f o r m a t i o n remains a l m o s t c o n s t a n t .  Davidson  (35) and Amick e m p i r i c a l l y derived the following equation f o r t h e maximum b u b b l e f r e q u e n c y i n t h e a i r - w a t e r system: f  where f max  =12.3 Q do" (1.2) max = maximum f r e q u e n c y o f b u b b l e f o r m a t i o n 0  13  0 , 4 3  Q = v o l u m e t r i c gas f l o w r a t e do = o r i f i c e d i a m e t e r (iii) rates  (2100<N  as a j e t . the  Non-homogeneous j e t : A t v e r y h i g h gas f l o w ) t h e b u b b l e stream c a n b e s t be d e s c r i b e d  The l a r g e r b u b b l e s o r a i r - s t r e a m i s s u i n g  from  o r i f i c e v i r t u a l l y explode i n t o small bubbles very c l o s e  to the o r i f i c e .  L e i b s o n e t a l (37) have measured t h e v a r i a t i o n o f b u b b l e s i z e w i t h Reynold's number o v e r a l l t h e b u b b l i n g  9  regimes.  T h e i r c o r r e l a t i o n f o r t h e a i r - w a t e r system  i s p r e s e n t e d g r a p h i c a l l y as F i g u r e 1.  I t can be seen  t h a t t h e bubble s i z e d e c r e a s e s r a p i d l y w i t h i n c r e a s i n g Reynold's number above N_  = 2100, and t h a t f o r 10,000<  Ke.  N„ t h e mean bubble d i a m e t e r i s almost c o n s t a n t a t 0.5 Re. cm.  10  F i g u r e 1.  V a r i a t i o n of mean bubble d i a m e t e r w i t h o r i f i c e d i a m e t e r and Reynolds number f o r the a i r - w a t e r system. From L e i b s o n e t a l ( 3 7 ) .  11  1.2.2.  Shape  and R i s e V e l o c i t y o f B u b b l e s  I n a d d i t i o n t o t h e work on b u b b l e f o r m a t i o n , some i n v e s t i g a t o r s have been c o n c e r n e d w i t h t h e shape and  rise  b e h a v i o u r o f e i t h e r s i n g l e b u b b l e s o r b u b b l e c h a i n s (27, 30, 32 and 55-59) o r o f b u b b l e swarms (36,56, 6 0 ) .  As  was t h e c a s e w i t h the t o p i c o f b u b b l e f o r m a t i o n , i t i s c o n v e n i e n t when d i s c u s s i n g the shape and r i s e v e l o c i t y o f b u b b l e s t o speak o f r e g i o n s o f b e h a v i o u r , i n t h i s c a s e o f r e g i o n s d e f i n e d by a range o f b u b b l e R e y n o l d ' s number (  )  •  b (i)  Very small bubbles ( N ^ Re v e l o c i t y d e f i n e d by S t o k e s law:  ^ 2)rise at a terminal  D  b  1  U  where u  T  =  -4^-  g  (p _p ) L  (1.3)  G  = t e r m i n a l rise v e l o c i t y of the bubble  d, = b u b b l e d i a m e t e r b y  L  = v i s c o s i t y of the l i q u i d .  The bubblesmay be c o n s i d e r e d t o behave as r i g i d s p h e r e s , (ii)  L a r g e r s p h e r i c a l b u b b l e s (2 <j N_ K e  < 400)  rise  b  a t a v e l o c i t y w h i c h i s up t o 50% g r e a t e r t h a n t h a t p r e d i c t e d by S t o k e s ' law.  T h i s b e h a v i o u r has been a t t r i b u t e d t o gas  c i r c u l a t i o n w i t h i n the bubble which causes motion a t the g a s - l i q u i d i n t e r f a c e and c o n s e q u e n t l y r e d u c e s t h e d r a g f o r c e .  12  (iii)  Bubbles i n t h e range 400 <  <5000 tend K e  b  t o f o l l o w a h e l i c a l o r z i g - z a g p a t h and a r e s p h e r o i d a l or e l l i p s o i d a l i n shape. (iv)  B u b b l e s l a r g e r t h a n 1 cm i n e q u i v a l e n t  d i a m e t e r (5000 < N R  S  J ) 3  assume a s p h e r i c a l - c a p shape.  A l t h o u g h t h e y tend t o o s c i l l a t e s l i g h t l y as t h e y r i s e , t h e y appear t o r i s e a t a u n i f o r m v e l o c i t y w h i c h i s i n dependent o f t h e p h y s i c a l p r o p e r t i e s o f t h e l i q u i d . D a v i e s and T a y l o r  (55) d e r i v e d t h e f o l l o w i n g e q u a t i o n  f o r the t e r m i n a l v e l o c i t y of a s p h e r i c a l - c a p bubble: u,p = 1.02 { - ^ - )  (1.4)  h  where d^ = e q u i v a l e n t d i a m e t e r (diameter  o f a sphere o f  e q u i v a l e n t volume)  In a d d i t i o n , t h e r e h a v e been i n v e s t i g a t i o n s c o n c e r n i n g the r i s e b e h a v i o u r o f b u b b l e s as a f u n c t i o n o f p h y s i c a l properties of the l i q u i d .  D a t t a e t a l (30) and A b d e l -  A a l e t a l (59) agree t h a t bubble volume i n c r e a s e s l i q u i d surface tension;  with  b u t whereas D a t t a f i n d s v e r y  l i t t l e v i s c o s i t y e f f e c t , Abdel-Aal i n l i q u i d s o f lower v i s c o s i t i e s .  f i n d s l a r g e r bubbles Siemes and Gunther ( 3 6 ) ,  when v i e w i n g bubble swarms, a l s o found t h a t i n c r e a s i n g the s u r f a c e t e n s i o n i n c r e a s e s t h e bubble volume  (they  measured a d e c r e a s e i n s p e c i f i c s u r f a c e area) and d e t e r mined t h a t i n c r e a s i n g t h e v i s c o s i t y  ( t o above 20cp) p r o -  duces m o s t l y l a r g e bubbles w i t h i n a narrow s i z e  range  because the v i s c o u s l i q u i d does not p e r m i t s t r o n g t u r b u l e n c e above the n o z z l e (which would n o r m a l l y cause bubble  break-up).  14  1.2.3  Homogenous J e t s  1.2.3.1  B e h a v i o u r o f Homogeneous J e t s  When a f l u i d o f u n i f o r m i n i t i a l v e l o c i t y i s discharged  ( u = const.) 0  i n t o a f l u i d medium a t a n g e n t i a l s e p a r a t i o n  s u r f a c e i s c r e a t e d between t h e moving f l u i d , o r j e t , and the ambient medium ( F i g u r e 2 ) . Parameters such as f l o w v e l o c i t y , t e m p e r a t u r e , and s p e c i e c o n c e n t r a t i o n  experience  t a n g e n t i a l separation while the s t a t i c pressure i s constant. The  t a n g e n t i a l separation surface i s inherently unstable,  c a u s i n g e d d i e s t o move i n a d i s o r d e r l y f a s h i o n b o t h a l o n g and a c r o s s t h e stream, which i n t u r n e f f e c t a t r a n s v e r s e t r a n s f e r o f momentum, heat, and c o n s t i t u e n t s o r mass. i s , t h e n , a boundary l a y e r  a c r o s s which t h e s e  There  parameters  v a r y c o n t i n u o u s l y between t h e i r i n i t i a l v a l u e s i n t h e d i s c h a r g i n g f l u i d and t h e i r v a l u e s i n t h e ambient medium.  The  j e t expands by e n t r a i n i n g f l u i d from t h e  s u r r o u n d i n g medium.  Consequent t o t h i s e n t r a i n m e n t t h e  parameters o f v e l o c i t y , temperature and c o n c e n t r a t i o n become more d i f f u s e and t h e c o r e o f f l u i d w i t h i n which the parameters remain a t i n i t i a l v a l u e s g r a d u a l l y d i m i n i s h e s . The  l e n g t h o f t h e j e t over which t h i s " p o t e n t i a l c o r e "  e x i s t s i s termed t h e i n i t i a l f l o w r e g i o n i n F i g u r e 2, and t y p i c a l l y has a l e n g t h o f between f o u r and s i x n o z z l e diameters.  A s h o r t d i s t a n c e downstream from t h e i n i t i a l  15  F i g u r e 2.  Schematic diagrams of j e t f l o w showing p o t e n t i a l f l o w c o r e (shaded area) and velocity p r o f i l e s at various distances from o r i f i c e . From S z e k e l y and Themelis (85).  16  r e g i o n t h e f l o w becomes f u l l y developed.  The e n t i r e  j e t may now be viewed as a boundary l a y e r s i n c e t h e r e i s no l o n g e r a c e n t r a l core o f c o n s t a n t v a l u e s . The j e t v e l o c i t y decreases  i n a downstream d i r e c t i o n  and s i m i l a r l y o t h e r parameters approach ambient v a l u e s . T y p i c a l v e l o c i t y p r o f i l e s a t v a r i o u s d i s t a n c e s from the n o z z l e a r e i l l u s t r a t e d i n F i g u r e 3. f i l e s a r e expressed  I f these  pro-  d i m e n s i o n l e s s l y , as a f r a c t i o n o f  the c e n t e r l i n e v a l u e a t each c r o s s - s e c t i o n , a l l t h e c u r v e s w i l l c o i n c i d e , as shown i n F i g u r e 4.  Similar  p r o f i l e s may be drawn f o r d i m e n s i o n l e s s temperature and dimensionless  concentration.  Abramovich (61) and  Schlichting  (62) p r o v i d e  comprehensive t r e a t m e n t s o f t u r b u l e n t j e t t h e o r y and boundary l a y e r t h e o r y r e s p e c t i v e l y and a r e recommended f o r ;raore d e t a i l e d treatment  of t h i s subject.  80 "T  Distance from axis, r, cm  F i g u r e 3.  J e t velocity p r o f i l e s i n r a d i a l sections at d i f f e r e n t d i s t a n c e s (X) from o r i f i c e . From S z e k e l y and Themelis ( 8 5 ) .  — o X=0.2M • X=0,35M * J: =0.50 M © x-0.60M A J:=0,75M  •o  -4^ Figure 4.  #f  ^  IS  £  Dimensionless v e l o c i t y p r o f i l e i n a plane j e t . From Abramovich (61).  00  19  J e t Cone A n g l e  1.2.3-2  Once t h e j e t f l o w becomes f u l l y d e v e l o p e d , t h e o u t e r envelope o f t h e j e t expands c o n i c a l l y , as though the j e t were i s s u e d from a p o i n t source l o c a t e d a t t h e apex o f t h e cone, o r t h e " j e t p o l e "  ( F i g u r e 2 ) . The  i n c l u d e d a n g l e o f t h i s cone, known as t h e j e t cone angle,  i s a v i t a l parameter o f a t u r b u l e n t j e t as i t  provides  an i n d i c a t i o n o f t h e degree t o which t h e j e t  i n t e r a c t s w i t h t h e ambient f l u i d , an i m p o r t a n t a s p e c t of i t s h e a t , mass, and momentum t r a n s f e r c a p a b i l i t i e s . I t i s n a t u r a l , t h e n , t h a t many i n v e s t i g a t o r s have attempted t o measure t h i s parameter as a f u n c t i o n of t h e j e t system.  Binnie  (63) i n j e c t e d a water j e t  v e r t i c a l l y downwards i n water and found t h a t t h e j e t expanded a t a cone a n g l e o f 1 4 ° .  P a b s t and B o h l (64)  studied the mixing of a coal-gas j e t with s t a t i o n a r y a i r and found t h a t t h e j e t expanded more q u i c k l y t h a n a s i m i l a r a i r j e t i n a i r , w h i l e C o r r s i n and U b e r o i (65) d e t e r m i n e d , by b l o w i n g a h o t a i r j e t i n t o c o o l a i r , that a reduction i n the density of the j e t r e l a t i v e t o t h e r e c e i v i n g medium i n c r e a s e s t h e r a t e o f s p r e a d . Rawn and Palmer ( 6 7 ) , s t u d y i n g t h e e x t e n t o f sewage d i s t r i b u t i o n i n sea w a t e r , measured t h e cone a n g l e o f a v e r t i c a l l y - r i s i n g sewage j e t t o be about 1 4 ° .  20  Donald and S i n g e r (66) s t u d i e d a i r / a i r ,  water/  w a t e r , sugar s o l u t i o n / s u g a r s o l u t i o n , and h y d r o g e n - i n t o air  j e t s , and measured cone a n g l e s o f between 14° and  24.5°, w i t h t h a t f o r t h e water j e t b e i n g 14° and f o r t h e a i r j e t , 20°.  On t h e b a s i s o f t h e s e r e s u l t s t h e y  proposed t h e e m p i r i c a l r e l a t i o n s h i p : tan  0 c  / 2 = 0.238 v  (1.5)  0 , 1 3 3  i n which t h e cone a n g l e i s a f u n c t i o n o n l y o f t h e k i n e m a t i c v i s c o s i t y of the j e t f l u i d .  S i n c e t h e Reynold's number  i s i n v e r s e l y p r o p o r t i o n a l t o the kinematic v i s c o s i t y , they c o n c l u d e t h a t an i n c r e a s e i n t h e Reynold's number produces a decrease i n t h e j e t a n g l e .  21  1.2.3.3  E f f e c t o f D e n s i t y D i f f e r e n c e s Upon J e t T r a j e c t o r y  When a j e t i s i n j e c t e d h o r i z o n t a l l y i n t o a s t i l l medium comprised o f t h e j e t f l u i d o r o f a f l u i d o f s i m i l a r d e n s i t y , t h e j e t p e n e t r a t e s u n t i T i t s e v e n t u a l decay a l o n g a s t r a i g h t l i n e known as t h e j e t t r a j e c t o r y .  I n t h i s case  of a c o n s t a n t - d e n s i t y j e t , t h e j e t t r a j e c t o r y i s c o i n c i d e n t w i t h t h e n o z z l e c e n t e r l i n e and i s t h e geometric  center  of t h e j e t as w e l l as t h e l o c u s o f p o i n t s o f g r e a t e s t velocity.  I f , however, t h e j e t i s i n j e c t e d  horizontally  i n t o a medium o f , s a y , g r e a t e r d e n s i t y than t h e j e t f l u i d , the j e t tends t o r i s e due t o t h e d e n s i t y d i f f e r e n c e between t h e two f l u i d s .  I n t h i s case t h e t r a j e c t o r y which  b e s t d e s c r i b e s t h e p a t h o f t h e j e t f i r s t emerges  tangent  to t h e n o z z l e c e n t e r l i n e b u t then c u r v e s upwards t o l i e c e n t r a l l y w i t h i n t h e j e t envelope.  Horn and T h r i n g  (68) i n v e s t i g a t e d t h e e f f e c t o f  d e n s i t y d i f f e r e n c e s on t h e p a t h o f j e t s by h o r i z o n t a l l y i n j e c t i n g a magnetite s l u r r y i n t o water.  They assumed  t h a t t h e j e t cone angle was n o t a f u n c t i o n o f t h e m a g n e t i t e to-water d e n s i t y r a t i o  and t h a t t h e j e t t r a j e c t o r y would  most s u i t a b l y be p l a c e d s y m m e t r i c a l l y w i t h i n t h e j e t envelope.  A d i m e n s i o n l e s s e x p r e s s i o n was then  to d e s c r i b e t h e v e r t i c a l d i s p l a c e m e n t  developed  of the j e t a x i s  as a f u n c t i o n o f both v a r y i n g d e n s i t y and j e t v e l o c i t y .  22  In a l a t e r paper, Bosanquet, Horn and T h r i n g (69) d e r i v e d a more complex e x p r e s s i o n f o r t h e j e t t r a j e c t o r y and envelope by assuming t h a t j e t momentum i s c o n s e r v e d , and t h a t t h e r a d i a l d i s t r i b u t i o n s of v e l o c i t y and  effluent  c o n c e n t r a t i o n remain a x i a l l y symmetric even when the j e t f o l l o w s a curved path.  The m a g n e t i t e - w a t e r system  was  used t o t e s t the p r e d i c t i o n s . Abraham (70) d e t e r m i n e d t h a t t h e c u r v a t u r e of a h o r i z o n t a l l y - i n j e c t e d j e t due t o the d e n s i t y d i f f e r e n c e between t h e j e t f l u i d and t h e ambient medium depends on t h e magnitude of t h e m o d i f i e d Froude number, N^  r  l a r g e c u r v a t u r e c o r r e s p o n d i n g t o s m a l l values o f  1.2.4  Gas J e t s i n L i q u i d s - Heterogeneous  1.2.4.1.  , with Kr  Jets  General Considerations  A h o r i z o n t a l l y - i n j e c t e d gas j e t i n a l i q u i d i n v o l v e s a l l of t h e c o n c e p t s p r e v i o u s l y c o n s i d e r e d : - bubble f o r m a t i o n , break-up and c o a l e s c e n c e - bubble r i s e b e h a v i o u r and  shape  - d i s t r i b u t i o n of v e l o c i t y , t e m p e r a t u r e and  gas  c o n c e n t r a t i o n between a c e n t r a l c o r e and an outer  boundary  - c o n i c a l e x p a n s i o n a t an a n g l e which i s i n some way dependent upon the j e t system. - t r a j e c t o r y c u r v a t u r e due t o buoyancy  force.  23  as w e l l as the added c o m p l i c a t i o n s t h a t gas c o n c e n t r a t i o n does not vary c o n t i n u o u s l y , but i n d i s c r e t e pockets or bubbles, and that the j e t i s i n s t a n t a n e o u s l y u n s t a b l e and is constantly fluctuating.  I f the j e t i s viewed  over a  p e r i o d of time, however, i t can be seen t h a t the j e t envelope f l u c t u a t e s about a mean v a l u e and t h a t the timeaveraged gas c o n c e n t r a t i o n does v a r y c o n t i n u o u s l y .  It i s  through the technique o f time-averaging t h a t many of the concepts developed f o r the case o f homogeneous j e t s may be adopted t o f a c i l i t a t e the d e s c r i p t i o n of heterogeneous j ets.  1.2.4.2  Previous Work  In 1940 Kazanstev  (71) s t u d i e d the mechanics o f  a gas j e t i n a Bessemer bath u s i n g an a i r - m e r c u r y  system.  Although p r i m a r i l y concerned w i t h the degree o f metal e j e c t i o n from the bath he determined  t h a t the a i r j e t  i n mercury i s i n the form of metal d r o p l e t s d i s p e r s e d i n the gas. The o p e r a t i n g c o n d i t i o n s i n these t e s t s a r e not c l e a r , however, and i t i s not c e r t a i n t h a t the experimental method i s r e l i a b l e .  He concluded t h a t s m a l l  diameter n o z z l e s a t deep submergence would p r o v i d e optimum o p e r a t i o n w i t h reduced metal  ejection.  Deev e t a l (72) measured l i q u i d entrainment the gas o u t l e t of a model c o n v e r t e r .  through  In the course o f  24  t h e i r i n v e s t i g a t i o n s i n t o l i q u i d e j e c t i o n they  concluded  t h a t b e s t m i x i n g i n t h e b a t h i s o b t a i n e d by d i r e c t i n g the t u y e r e s h o r i z o n t a l l y o r upwards a t a s m a l l a n g l e . They a l s o  i d e n t i f i e d l i q u i d v i s c o s i t y as t h e most  i m p o r t a n t parameter i n t h e i r s t u d i e s on s p l a s h i n g . Themelis and Schmidt (73) s t u d i e d t h e d e o x i d a t i o n o f l i q u i d copper by a submerged gas j e t blown v e r t i c a l l y upwards through the b a t h .  Gas phase c o n t r o l p r e v a i l e d  a t m e l t c o n c e n t r a t i o n s above 0.1 p e r c e n t oxygen, and k g C ' , the p r o d u c t o f the g a s - f i l m mass t r a n s f e r c o e f f i c i e n t and the s p e c i f i c i n t e r f a c i a l a r e a  ( < 0 was  (kg)  constant w i t h  d i s t a n c e a l o n g t h e j e t a x i s and n e a r l y p r o p o r t i o n a l t o the o r i f i c e Reynold's Re  0  <9100.  number (Re ) Q  i n t h e range 1000<  They a l s o note t h a t a t r a n s i t i o n o c c u r s  between the cone zone of the j e t and a column zone of n e a r l y c o n s t a n t c r o s s - s e c t i o n i n which t h e v e l o c i t y o f the g a s - l i q u i d d i s p e r s i o n may  be assumed t o be c o n s t a n t .  In 1969 Themelis e t a l (74) d e r i v e d an e q u a t i o n f o r the t r a j e c t o r y of a gas j e t h o r i z o n t a l l y  injected  i n t o a l i q u i d on t h e b a s i s o f c o n t i n u i t y and momentum b a l a n c e r e l a t i o n s h i p s , a l l o w i n g t h e j e t r i s e under the i n f l u e n c e of buoyancy.  The cone a n g l e of t h e j e t was  measured a t 20° f o r the a i r - w a t e r system, and w i t h t h i s v a l u e the t h e o r e t i c a l e q u a t i o n showed good agreement w i t h p h o t o g r a p h i c measurements of an a i r j e t i n water.  25  The model  was  used t o d e s c r i b e t h e j e t t r a j e c t o r y i n  a copper c o n v e r t e r w i t h t h e s u p p o r t i n g argument t h a t "agreement between t h e o r y and e x p e r i m e n t f o r a system where t h e l i q u i d / g a s d e n s i t y r a t i o i s n e a r l y  900,  i n d i c a t e s t h a t the j e t t r a j e c t o r y equation d e r i v e d  should  a l s o be a p p l i c a b l e t o t h e c a s e o f an a i r j e t i n l i q u i d matte o r c o p p e r . "  Nemchenko e t a l (75) measured t h e cone a n g l e a n i t r o g e n j e t i n w a t e r t o be 23°. considered  This value  of  was  t o be a p p l i c a b l e t o l i q u i d m e t a l systems  the hydrodynamics o f t h e l a d l e d e g a s s i n g d i s c u s s e d through c a l c u l a t i o n .  and  o f s t e e l were  An e q u a t i o n was  presented  t o d e s c r i b e t h e p e n e t r a t i o n d i s t a n c e of a h o r i z o n t a l l y injected j e t ; The  authors  t h e c o e f f i c i e n t s were e m p i r i c a l l y o b t a i n e d .  concluded  that nozzles d i s t r i b u t e d  throughout  t h e e n t i r e bottom of the l a d l e and r e l e a s i n g s i n g l e b u b b l e s would r e s u l t i n f a r more e f f i c i e n t gas usage t h a n N e i t h e r t h e problems of n o z z l e - p l u g g i n g a t low nor t h e economics o f a s l o w - b u b b l i n g  I n 1971, s t u d y on gas  Wraith  lancing.  jets.  flowrates  p r o c e s s were d i s c u s s e d .  (76) r e p o r t e d an a i r - w a t e r model He q u a l i t a t i v e l y d e s c r i b e s  the  l a t e r a l l y - i n j e c t e d j e t as a "compact gas d i s p e r s i o n " produced by p r o g r e s s i v e m i x i n g a l o n g the  trajectory.  A s o n i c j e t i n j e c t e d downward a t 45° was  found t o g i v e  deeper p e n e t r a t i o n and  a more d i f f u s e d i s p e r s i o n t h a n a  26  h o r i z o n t a l j e t , however i t i s made c l e a r t h a t d i f f e r e n c e s i n j e t behaviour  "the  between water and  liquid  metals, p a r t i c u l a r l y regarding penetration d i s t a n c e , l i m i t the r e l e v a n c e of the water model." S p e s i v t s e v and S t r e k a l o v s k i i s a t i n g n a t u r e of the j e t t h a t immediately  (77) noted the p u l -  as w e l l as the  observation  a t the p o i n t of i n j e c t i o n t h e j e t i s  widened by t h r e e t o f o u r t i m e s .  Presumably t h i s  observation  a p p l i e s t o a l l g a s - l i q u i d systems which were t e s t e d .  An  e q u a t i o n i s proposed d e s c r i b i n g t h e h o r i z o n t a l l e n g t h or p e n e t r a t i o n of the j e t as a f u n c t i o n of Froude number; the r e l a t i o n s h i p appears t o be i n r e a s o n a b l e experimental  agreement w i t h  d a t a o b t a i n e d from g a s - w a t e r , - Z n C l  and - T h o u l e t s 1  2  solution,  s o l u t i o n systems but d i s p l a y s r e l a t i v e l y  poorer agreement w i t h r e s u l t s of t e s t s i n t h e a i r mercury system. S p e s i v t s e v e t a l (78) c l a i m t h a t i n i s o t h e r m a l models the f a c t o r which d e t e r m i n e s the p e n e t r a t i o n d i s t a n c e of a h o r i z o n t a l l y - i n j e c t e d j e t i s the d e n s i t y of the l i q u i d .  S u r f a c e t e n s i o n and v i s c o s i t y of the  liquid  are s a i d t o have an e f f e c t i n some c a s e s , but t h i s i s not w e l l defined yet.  The  a u t h o r s mention t h a t s t u d i e s of  h o r i z o n t a l gas i n j e c t i o n i n t o m e l t s show a p i c t u r e of i n t e r a c t i o n s i m i l a r t o t h a t o b s e r v e d i n t h e gas-mercury system.  U n f o r t u n a t e l y they do not e l a b o r a t e on t h i s i n  more d e t a i l .  27  Igwe  e t a l (7 9) s t u d i e d j e t p e n e t r a t i o n , b u b b l e  d i s p e r s i o n and l i q u i d s p l a s h i n t h e  nitrogen-water  system a s a f u n c t i o n o f n o z z l e s i z e and d e s i g n , gas d r i v i n g p r e s s u r e , and l i q u i d d e n s i t y .  F o r h o r i z o n t a l gas  i n j e c t i o n t h e y found a s t r a i g h t - l i n e r e l a t i o n s h i p between h o r i z o n t a l p e n e t r a t i o n d i s t a n c e and a j e t - f o r c e number, N, g i v e n by t h e p r o d u c t o f t h e gas d r i v i n g p r e s s u r e and t h e n o z z l e d i a m e t e r .  I n a d d i t i o n , they s t a t e t h a t  above an ambient l i q u i d d e n s i t y o f 2 . 2 5 g/cm3 t h e j e t p e n e t r a t i o n appears t o be i n s e n s i t i v e t o d e n s i t y Brimacombe e t a l (80) e x p l o r e d  aspects  increases.  o f mass  t r a n s f e r between a h o r i z o n t a l submerged j e t o f 1 p e r c e n t SO2 i n j e c t e d i n t o an aqueous s o l u t i o n o f 0 . 3 p e r c e n t hydrogen p e r o x i d e .  From t h e measured a b s o r p t i o n r a t e s ,  and u s i n g t h e t r a j e c t o r y e q u a t i o n  o f Themelis e t a l ( 7 4 ) ,  v a l u e s o f t h e p r o d u c t o f t h e gas phase mass t r a n s f e r c o e f f i c i e n t and i n t e r f a c i a l  area per u n i t l e n g t h o f  1  trajectory,  kgQ " 2  , were d e r i v e d .  diameter, the r a t i o of  ks02  '  t  o  For a given ^  a s  f-*-  ow r  a  t  t o be independent o f o r i f i c e R e y n o l d ' s number. of l i q u i d phase c o n t r o l , c o n s e c u t i v e  e  orifice was found Regions  c o n t r o l , and g a s -  phase c o n t r o l were d e f i n e d . Turkdogan (81) r e c e n t l y has s u g g e s t e d t h a t a submerged gas j e t i n a l i q u i d i s composed o f two zones:  28  the f i r s t , i n which f i n e m i s t - l i k e d r o p l e t s of are d i s p e r s e d  liquid  i n a c o n t i n u o u s gas phase, and t h e second  zone c o n s i s t i n g of gas bubbles i n a c o n t i n u o u s l i q u i d phase, caused by t h e l i q u i d fragments i n the f i r s t c o l l i d i n g and c o a l e s c i n g downstream.  zone  In a d d i t i o n ,  suggests t h a t the s u r f a c e t e n s i o n of the l i q u i d  he  might  w e l l be the i m p o r t a n t parameter i n t h e dynamics o f such j e t s .  However, no e v i d e n c e i s o f f e r e d t o s u p p o r t  e i t h e r of t h e s e p o s t u l a t e s . T i e n and Turkdogan  (82) have a l s o proposed a t h r e e  zone model of a gas j e t i n a l i q u i d .  The f i r s t  c o n s i s t s of a gas pocket c o n t a i n i n g d i s p e r s e d  zone liquid  phase and p e r s i s t s f o r 28 n o z z l e d i a m e t e r s downstream. In the second zone the gas stream t r a n s f o r m s t o gas b u b b l e s and i n the t h i r d zone the b u b b l e s grow u n t i l t h e t e r m i n a l v e l o c i t y i s approached.  The model p r e d i c t s  t h a t the u l t i m a t e bubble s i z e i s a f u n c t i o n o f gas v e l o c i t y , gas and l i q u i d d e n s i t i e s , and the  kinematic  v i s c o s i t y and s u r f a c e t e n s i o n of the l i q u i d , but i s independent o f the o r i f i c e d i a m e t e r .  The e n t r a i n m e n t  of l i q u i d by bubbles i s s a i d t o be d i r e c t l y  proportional  to the flow r a t e .  M. I s h i b a s h i (83) r e c e n t l y r e p o r t e d the r e s u l t s  29  of s t u d i e s on a i r j e t s blown b o t h h o r i z o n t a l l y v e r t i c a l l y upwards i n t o water.  and  He c l a i m s t h a t a t  s u f f i c i e n t l y h i g h p r e s s u r e t h e r e i s no b a c k - p e n e t r a t i o n and t h e j e t d i a m e t e r a t t h e o r i f i c e e q u a l s t h e o r i f i c e diameter.  Both f o r w a r d and back p e n e t r a t i o n o f the j e t s  are e x p r e s s e d d i m e n s i o n l e s s l y as f u n c t i o n s of the cube r o o t of the Froude number.  30  CHAPTER 2 OVERVIEW OF THE PRESENT WORK  I t i s apparent from an e x a m i n a t i o n o f t h e e x i s t i n g l i t e r a t u r e t h a t v e r y l i t t l e i s known o f t h e b e h a v i o u r o f submerged gas j e t s i n l i q u i d s and f u r t h e r , because o f the d i f f i c u l t i e s i n measurement, t h a t no work has attempted a detailed description  of the p h y s i c a l  characteristics  of submerged gas j e t s i n l i q u i d m e t a l s . been d i r e c t e d  T h i s work has  toward t h e study o f an i s o t h e r m a l ,  non-  r e a c t i v e g a s - l i q u i d m e t a l system by t h e d i r e c t measurement o f t h e p h y s i c a l c h a r a c t e r i s t i c s o f h o r i z o n t a l l y i n j e c t e d submerged a i r j e t s i n mercury. system has a l s o been i n v e s t i g a t e d  The a i r - w a t e r  p r i m a r i l y as an a c c e s s o r y  to a s s i s t i n the understanding of the air-mercury  The main o b j e c t i v e s  system.  o f t h e p r e s e n t work were as  follows: (i)  To p r e s e n t a d e t a i l e d d e s c r i p t i o n  o f a 3-  d i m e n s i o n a l h o r i z o n t a l l y - i n j e c t e d submerged a i r j e t i n mercury.  Such a d e s c r i p t i o n  includes  basic observations  of t h e j e t shape and p h y s i c a l appearance as w e l l as d e t a i l e d mapping o f gas volume f r a c t i o n and bubble frequency throughout t h e j e t .  31  (ii)  To study the e f f e c t of t u y e r e d i a m e t e r  and Froude number on t h e shape o f the j e t and on d i s t r i b u t i o n s of gas volume f r a c t i o n and  the  bubble  frequency. (iii)  To d e f i n e i m p o r t a n t  p r o p e r t i e s of  system such as j e t cone a n g l e , j e t t r a j e c t o r y , z o n t a l p e n e t r a t i o n d i s t a n c e and discuss t h e i r significance of a gas  the hori-  j e t d i a m e t e r and  as c h a r a c t e r i s t i c  j e t - l i q u i d m e t a l system.  The  to  parameters  effectsof  Froude number and t u y e r e d i a m e t e r upon t h e s e parameters were s t u d i e d i n the a i r - m e r c u r y (iv)  system.  To d e s c r i b e the p h y s i c a l p r o c e s s o c c u r r i n g  i n the formation  and development of a submerged gas j e t  i n a l i q u i d i n a p r a c t i c a l manner t h a t f a c i l i t a t e s understanding  of events occurring i n more complex  i n d u s t r i a l systems of m e t a l l u r g i c a l (v)  To assess  o f t h e i r i n f l u e n c e upon j e t  steelmaking  liquid  s u r f a c e t e n s i o n i n terms  behaviour.  F i n a l l y , t o r e l a t e the r e s u l t s of  i n the a i r - m e r c u r y and  interest.  p h y s i c a l p r o p e r t i e s of the  such as d e n s i t y , v i s c o s i t y , and  (vi)  the  studies  system t o i n d u s t r i a l copper c o n v e r t i n g  systems and t o d i s c u s s s e v e r a l of  the  phenomena o c c u r r i n g i n i n d u s t r i a l o p e r a t i o n s i n terms of the p r e s e n t  experimental  results.  32  CHAPTER 3 APPARATUS AND PROCEDURES  3.1  A i rjets injected horizontally into  Submerged a i r j e t s were i n j e c t e d  mercury.  horizontally  i n t o a b a t h o f mercury t h r o u g h an i n t e r c h a n g e a b l e s t r a i g h t bore n o z z l e .  Time-averaged,  p o i n t v a l u e s o f gas volume  f r a c t i o n and bubble f r e q u e n c y were measured as a f u n c t i o n of 3 - d i m e n s i o n a l p o s i t i o n i n t h e b a t h by means o f a moveable e l e c t r o r e s i s t i v i t y probe and accompanying e l e c t r o n i c apparatus.  S l i g h t m o d i f i c a t i o n s and a d d i t i o n s  t o t h e b a s i c apparatus a l l o w e d t h e attempted measurements of gas v e l o c i t y and b a c k - p e n e t r a t i o n o f mercury nozzle.  into the  33  3.1.1  P h y s i c a l Apparatus  The  apparatus employed i n the study of  air-in-  mercury j e t s i s i l l u s t r a t e d s c h e m a t i c a l l y i n F i g u r e  5.  I t c o n s i s t e d of a c o n v e r t e r - s h a p e d v e s s e l c o n t a i n i n g the mercury, an a i r d e l i v e r y system t o s u p p l y  clean,  dry a i r t o the t u y e r e , an e l e c t r o r e s i s t i v i t y probe t o i n t e r c e p t and  sense the gas b u b b l e s a t v a r i o u s  p o i n t s i n the b a t h , and e l e c t r o n i c a p p a r a t u s t o measure and r e c o r d the i n f o r m a t i o n r e c e i v e d a t the probe t i p .  Electronic Apparatus Including Integrator and Counter  Electroresistivity Probe  Mercury Tank  Air From Compressor i j Cyclone Air Figure 5  Supply  System  Schematic of apparatus of air-mercury j e t s .  employed  i n the study  CO  35  3.1.1.1  The A i r D e l i v e r y System  A i r was  s u p p l i e d t o the t u y e r e by a compressor 5 N  m a i n t a i n i n g a gauge p r e s s u r e o f 6.9 the p r e s s u r e was  The  /M  (100  psig.);  reduced near the apparatus by a H a r r i s  r e g u l a t o r and f i n e f l o w c o n t r o l was valve.  x 10  2  a i r was  e f f e c t e d by a needle  passed through a c y c l o n e - t y p e  centri-  f u g a l s e p a r a t o r and s t r a i n e r and then t h r o u g h a f i v e m i c r o n f i l t e r t o remove o i l , condensed w a t e r , and particulate.  Flow c o n d i t i o n s near the t u y e r e were  by a r o t a m e t e r , s y m m e t r i c a l l y f l a n k e d by two p r e s s u r e gauges.  solid monitored  Bourdon-type  The r e a d i n g s o f the two p r e s s u r e gauges  were averaged t o determine  the p r e s s u r e w i t h i n the  rotameter,  a l l o w i n g mass f l o w r a t e s t o be a c c u r a t e l y c a l c u l a t e d . use, a l l f l o w meters were c a l i b r a t e d i n d e p e n d e n t l y by d i f f e r e n t methods, and were then c r o s s - c h e c k e d o t h e r as a f i n a l i n s u r a n c e a g a i n s t e r r o r ) . a t the t u y e r e e x i t atmospheric  was  Gas  (Before two  a g a i n s t each flow  c a l c u l a t e d f o r the c o n d i t i o n o f  p r e s s u r e p l u s m e r c u r o - s t a t i c head a t t h a t  point. .3.1.1.2.  The Mercury Tank  The mercury was v e s s e l made o f 40.6  contained i n a  cm I.D.  cm.long and s e a l e d w i t h 1.9  converter-shaped  carbon s t e e l p i p e , c u t cm.  -  thick plexiglass  25.4 end-  36  pieces  (Figures 6 & 7).  H o r i z o n t a l b a f f l e s were  f a s t e n e d t o the p l e x i g l a s s w a l l s t o p r e v e n t j e t d e f l e c t i o n due was  t o s l o p p i n g , and the c y l i n d r i c a l  t r u n c a t e d 8.9  cm.  tank  above i t s h o r i z o n t a l diameter  a l l o w the f i x t u r e o f t r a v e r s i n g equipment.  to  I n a con-  f i g u r a t i o n s i m i l a r t o copper c o n v e r t e r p r a c t i c e , a h o r i z o n t a l i n t e r c h a n g e a b l e t u y e r e was  Inserted  through  the s i d e w a l l o f the tank, l o c a t e d c e n t r a l l y between the p l e x i g l a s s end-pieces h o r i z o n t a l diameter.  and 15.2  cm.  below the  U n l i k e c o n v e r t e r p r a c t i c e , however,  the t u y e r e extended i n t o the b a t h  (up t o 10.2  cm.)  to  reduce the i n f l u e n c e o f the r e a r w a l l upon t h e j e t configuration. h e i g h t of 9.1  The b a t h was cm.  f i l l e d w i t h mercury t o a  above the t u y e r e c e n t e r l i n e .  Mounted d i r e c t l y on top of the tank was o r t h o g o n a l , graduated  a  3-dimensional,  t r a v e r s i n g system w h i c h r i g i d l y h e l d  the e l e c t r o r e s i s t i v i t y probe and a l l o w e d a c c u r a t e p l a c e ment of the probe t i p a t any p o i n t i n the b a t h . tank was gas was to  The  e n c l o s e d w i t h a l a r g e p l a s t i c bag and the o f f f o r c e d t o pass through  a granulated sulphur  remove any mercury vapour b e f o r e f i n a l d i s c h a r g e  atmosphere through a fume hood.  filter to  1-9 cm.  F i g u r e 6.  thick  Schematic of mercury  tank  38  F i g u r e 7.  P h o t o g r a p h s o f t h e c o n v e r t e r - t y p e t a n k and a n c i l l a r y apparatus used i n the a i r - m e r c u r y  tests.  39  3.1.1.3  The  E l e c t r o r e s i s t i v i t y Probe  S i n c e mercury i s an opaque f l u i d i t was  necessary  t o d e s i g n a probe w h i c h c o u l d "see" i n t o the b a t h  and  measure p o i n t - v a l u e q u a n t i t i e s o f gas volume f r a c t i o n and b u b b l e f r e q u e n c y .  The  e l e c t r o r e s i s t i v i t y probe used  i n t h i s work i s i l l u s t r a t e d i n F i g u r e The was  probe was  a length of m i l d s t e e l welding  turned to a needle-point  with cholorethene.  8.  The  and t h e n c l e a n e d and  s u r f a c e was  was  repeated  developed.  400K  for  2  degreased  then dip-coated  a t h i n l a y e r o f r e d G l y p t o l (a G e n e r a l E l e c t r i c f i n i s h ) and baked a t  rod which  hours;  with  insulating  t h i s procedure  s e v e r a l times u n t i l a hard, c o n s i s t e n t c o a t i n g An i n s u l a t e d copper w i r e was  soldered into a  h o l e p r e v i o u s l y d r i l l e d i n t o t h e t o p o f the r o d , and r o d was  encased i n h e a t - s h r i n k a b l e t u b i n g from t h e  of the needle-taper  was  over  For r i g i d i t y t h e assembly  then i n s e r t e d i n t o a m i l d s t e e l sheath which  roll-compressed  start  t o beyond t h e s o l d e r j o i n t and  t h e i n s u l a t e d copper w i r e .  the  was  near each end t o g r i p t h e r o d assembly  s e c u r e l y but not break the i n s u l a t i n g l a y e r s . t h e G l y p t o l c o a t i n g was  Finally  r e t i c u l a t e d from t h e t i p of  r o d u s i n g S t r i p - X , a commercial s o l v e n t marketed by E l e c t r o n i c s , l e a v i n g a b a r e s t e e l p o i n t .08 cm.  long  the G.C.  40  Insulated Wire  Copper  Heat Shrinkable Spaghetti-tubing Roll-compressed To Grip Securely Mild Steel Sheath  Mild Steel Rod Tapered To A Needle-point  Baked-on Over The Rod  Figure 8.  Glyptol Entire  Silicone Sealant Exposed Steel Tip  Schematic o f j e l e c t r o r e s i s t i v i t y  probe.  41  and 0.07 cm. a t i t s l a r g e s t d i a m e t e r . The probe used i n t h i s work i s s i m i l a r t o one w h i c h was f i r s t employed by N e a l and B a n k o f f  (84) f o r  t h e measurement o f l o c a l v o i d p r o p e r t i e s i n a mercuryn i t r o g e n two-phase f l o w system.  I n t h e p r e s e n t work,  however, t h e probe had t o be more m o b i l e t o e n a b l e  sampl-  i n g o f a l a r g e r volume y e t a t t h e same t i m e i t had t o be much more r i g i d t o endure t h e b u f f e t i n g o f t h e h i g h v e l o c i t y a i r j e t w i t h o u t d e f l e c t i n g from i t s s a m p l i n g point.  3.1.2.  Electronic  Apparatus  I t was mentioned  e a r l i e r that the e l e c t r o r e s i s t i v i t y  probe was d e s i g n e d t o "see" i n t o t h e b a t h , t o sense t h e events o c c u r r i n g a t a p a r t i c u l a r p o i n t .  T h i s was  a c c o m p l i s h e d by d e s i g n i n g an e l e c t r i c a l c i r c u i t  which  used t h e probe t i p and t h e s t e e l w a l l s o f t h e mercury t a n k as e l e c t r o d e s , c o u p l e d by t h e mercury When t h e probe t i p c o n t a c t e d mercury  i n t h e tank.  t h e c o u p l i n g was  c o m p l e t e , however, when . an a i r b u b b l e s u r r o u n d e d t h e probe t i p t h e c i r c u i t was b r o k e n . The e l e c t r o n i c a p p a r a t u s i l l u s t r a t e d i n F i g u r e 9 b a s i c a l l y c o n s i s t e d o f a power s u p p l y w h i c h caused a  Probe  33 a  800 &  AAAA  V\AA  Integrator Bounceless Switch  +5V DC Reg Power Supply  Counter  L  Timer  7IMW N3  Figure  9.  Schematic of e l e c t r o n i c apparatus study of air-mercury j e t s .  employed  i n the  43  c u r r e n t t o f l o w whenever t h e c i r c u i t was c l o s e d , an i n t e g r a t o r t o measure t h e f r a c t i o n o f t i m e d u r i n g w h i c h c u r r e n t was f l o w i n g , o r volume f r a c t i o n m e r c u r y , and a c o u n t e r t o c o u n t t h e number o f c i r c u i t i n t e r r u p t i o n s , o r bubble frequency.  A timer connected t o a bounceless  s w i t c h a l l o w e d a l l t h e e l e c t r o n i c equipment  t o be  s t a r t e d and s t o p p e d s i m u l t a n e o u s l y . 3.1.2.1.  The I n t e g r a t o r .  The i n t e g r a t o r i n t h e c i r c u i t was d e s i g n e d and b u i l t t o measure t h e t o t a l t i m e d u r i n g w h i c h t h e c i r c u i t was c l o s e d , i . e . t h e t i m e d u r i n g w h i c h t h e probe t i p was c o n t a c t i n g mercury.  The sample t i m e was chosen  sufficiently  l a r g e t h a t t h i s v a l u e c o u l d be n o r m a l i z e d t o r e a d volume f r a c t i o n mercury.  By d i f f e r e n c e , t h e volume f r a c t i o n o f  gas a t t h e sample p o i n t was d e t e r m i n e d .  3.1.2.2.  '-The Counter  The c o u n t e r was c o n n e c t e d p a r a l l e l t o t h e inte:g r a t o r t o r e c o r d t h e v o l t a g e p u l s e s caused by c i r c u i t interruptions.  I t was d e t e r m i n e d t h a t a b u b b l e  c e p t i n g t h e probe t i p and b r e a k i n g t h e c i r c u i t  intercaused  a p o s i t i v e voltage pulse across the i n t e g r a t o r , while a b u b b l e l e a v i n g t h e probe t i p and c l o s i n g t h e c i r c u i t caused a n e g a t i v e v o l t a g e p u l s e .  A Hamner  scintillation  44  c o u n t e r was m o d i f i e d t o count each p o s i t i v e v o l t a g e pulse  (above a c e r t a i n magnitude)  negative pulse.  but t o i g n o r e each  I n t h i s manner each bubble w h i c h  i n t e r c e p t e d and enveloped the probe t i p was o n l y once.  counted  When d i v i d e d by t h e sample t i m e , t h i s  total  count y i e l d e d a v a l u e o f bubble f r e q u e n c y .  3.1.2.3  The  Timer  A t i m e r was p r e s e t t o t h e d e s i r e d sample time and connected t o c o n t r o l a b o u n c e l e s s s w i t c h on t h e p r i m a r y circuit.  Thus, by a c t u a t i n g t h e timer b o t h t h e i n t e g r a t o r  and c o u n t e r were s e t i n t o o p e r a t i o n , and a t the end o f the d e s i r e d sample time b o t h were a u t o m a t i c a l l y stopped. D e t a i l e d c i r c u i t diagrams of the b o u n c e l e s s switch/power s u p p l y u n i t and t h e i n t e g r a t o r , b o t h of which were d e s i g n e d and b u i l t i n t h e e l e c t r o n i c s shop of t h e M e t a l l u r g y Department,  3.1.3.  a r e i n c l u d e d as Appendix I .  G e n e r a l O p e r a t i n g Procedure  The t i m e r was p r e s e t to a sample time of 58 seconds, the probe was p o s i t i o n e d t o sample t h e d e s i r e d p o i n t i n the b a t h , and the a i r f l o w was a d j u s t e d and a l l o w e d t o  45  stabilize.  The t i m e r was t h e n a c t i v a t e d , which i n t u r n  a c t i v a t e d the bounceless s w i t c h , thus c l o s i n g the c i r c u i t and a l l o w i n g t h e i n t e g r a t o r and c o u n t e r to. b e g i n recording.  A t t h e end o f the p r e s c r i b e d 58 seconds, t h e  t i m e r a u t o m a t i c a l l y caused the b o u n c e l e s s s w i t c h t o open, thus s t o p p i n g the i n t e g r a t o r and c o u n t e r .  Values  were r e c o r d e d . The gas volume f r a c t i o n and bubble f r e q u e n c y were measured a t 2000 t o 3000 d a t a p o i n t s per r u n , p r o v i d i n g a h i g h d e n s i t y 3 - d i m e n s i o n a l map  o f t h e j e t . Runs were  made f o r t u y e r e d i a m e t e r s of 0.325 cm. and 0.476 cm.,  over  a range of m o d i f i e d Froude numbers from 20 t o 300.  3.1.4  V e l o c i t y Measurements  V e l o c i t y measurements of the a i r j e t i n mercury a l s o attempted.  were  For t h i s purpose a d d i t i o n a l equipment  was added t o the above-mentioned  apparatus.  A solenoid  v a l v e was added t o t h e a i r l i n e i m m e d i a t e l y b e h i n d the t u y e r e and a s t o r a g e o s c i l l o s c o p e was connected i n p a r a l l e l t o the i n t e g r a t o r and c o u n t e r .  S u i t a b l e s w i t c h e s were  d e s i g n e d and connected such t h a t by t r i g g e r i n g the t i m e r the s o l e n o i d v a l v e was a u t o m a t i c a l l y c l o s e d ,  shutting  o f f the a i r s u p p l y , and s i m u l t a n e o u s l y the o s c i l l o s c o p e was t r i g g e r e d and began a s i n g l e sweep.  The  oscilloscope  46  recorded a square-wave " b l i p " each time a bubble passed the  probe t i p , and i t was intended t h a t by measuring the  time from a i r supply i n t e r r u p t the  probe, knowing the p o s i t i o n  average v e l o c i t y of the j e t .  t o the l a s t bubble p a s s i n g of the probe t i p , an  could be determined f o r v a r i o u s r e g i o n s  Since both bubble frequency and gas volume  f r a c t i o n were measured, the a d d i t i o n a l  i n f o r m a t i o n on  gas v e l o c i t y would enable bubble s i z e t o be  3.1.5.  calculated.  Measurements of Mercury Backflow Into the Tuyere  For  reasons t o be d i s c u s s e d l a t e r t h e r e was thought  to be a strong p o s s i b i l i t y o f mercury backflow i n t o the tuyere.  In an attempt t o d e t e c t t h i s behaviour the n o z z l e  illustrated  i n F i g u r e 10 was designed.  Two such n o z z l e s  •were c o n s t r u c t e d , one o f 0.325 cm. I.D. and the other of 0".4'76 cm. I.D. overall the  Both n o z z l e s were o f r o u g h l y the same  l e n g t h as the r e g u l a r t u y e r e s , but i n t h i s case  l a s t 7.5 cm. o r so was made o f t e f l o n .  T h i s allowed  two l e n g t h s of n i c k e l wire t o be I n s e r t e d through the nozzle wall,  p r o t r u d i n g i n t o the bore near the n o z z l e e x i t .  Each of these wires acted independently i n the same f u n c t i o n as the e l e c t r o r e s i s t i v i t y probe;  and they were,  one a t a time, connected i n t o the c i r c u i t d e t a i l e d replacing directed  the probe.  earlier,  In t h i s case, however, i n t e r e s t  was  t o measuring the f r a c t i o n o f time d u r i n g which  Figure  10.  S e c t i o n a l diagram the determination  of t e f l o n nozzle used of mercury backflow.  in  4>-  48  t h e n i c k e l s e n s o r was as  i n c o n t a c t w i t h a wave o f  mercury  w e l l as t h e f r e q u e n c y w i t h w h i c h t h i s b a c k f l o w  occurred.  T h i s t e s t , of course, r e q u i r e d the  mercury  wave be c o n t i n u o u s w i t h t h e b a t h , as t h e second e l e c t r o d e was  s t i l l the bath w a l l .  non-continuous  To a l l o w t h e measurement of  s p l a s h e s o f mercury b o t h s e n s o r s were  c o n n e c t e d as e l e c t r o d e s (one o f them r e p l a c i n g t h e t a n k wall i n this function). any mercury  This permitted the d e t e c t i o n of  d r o p l e t which contacted both sensors s i m u l t -  aneously.  3.1.6  E v a l u a t i o n o f Equipment  Performance  There were two p r i m a r y a r e a s o f c o n c e r n r e g a r d i n g equipment performance. to  One was t h a t t h e e l e c t r o n i c  response  a b u b b l e b r e a k i n g o r c l o s i n g t h e c i r c u i t s h o u l d be  f a s t and c l e a n ;  t h e o t h e r was t h a t t h e c o u n t e r s h o u l d  count each i n t e r c e p t i n g bubble once and o n l y once. f i r s t a s p e c t , t h a t o f t h e c i r c u i t r y r e s p o n s e , was  The tested  by v i e w i n g on a s t o r a g e o s c i l l o s c o p e t h e waveform produced by a b u b b l e i n t e r c e p t i n g and t h e n l e a v i n g t h e probe t i p . A t y p i c a l o s c i l l o s c o p e t r a c e o f such a b u b b l e i s shown in  F i g u r e 11.  A l l wave c o r n e r s a r e s t i l l  sharp  indicating  t h a t t h e b r e a k t i m e i s so s m a l l as t o be nonmeasurable a t t h i s t r a c e speed o f 2 msec, per major d i v i s i o n .  Figure  12 i s a s i m i l a r o s c i l l o s c o p e t r a c e o f f i v e b u b b l e s  inter-  49  F i g u r e 11.  A v o l t a g e pulse recorded at a t r a c e speed of 2 m s . / d i v i s i o n , or 500 cm./s  50  Figure  12.  F i v e f a s t v o l t a g e p u l s e s viewed a t a t r a c e speed of 1 m s / d i v i s i o n , or 1000 cm/s.  51  c e p t i n g and p a s s i n g the probe t i p i n q u i c k s u c c e s s i o n . The t r a c e speed i n t h i s case i s t w i c e t h a t o f F i g u r e 11. I t i s w o r t h n o t i n g t h a t b u b b l e s o f t h i s s m a l l s i z e were s t i l l p i e r c e d by the probe.  The second a r e a o f c o n c e r n , t h a t t h e c o u n t e r s h o u l d count each bubble once and o n l y once, was t e s t e d by t h e use o f a d u a l - c h a n n e l s t o r a g e o s c i l l o s c o p e .  One c h a n n e l  was connected t o the c o u n t e r such t h a t i t d i s p l a y e d a b l i p each t i m e the c o u n t e r r e g i s t e r e d a b u b b l e ; the o t h e r c h a n n e l was connected as i n the p r e v i o u s t e s t t o d i s p l a y t h e waveforms of p a s s i n g b u b b l e s .  The t r a c e s of b o t h  c h a n n e l s were s y n c h r o n i z e d and t r i g g e r e d s i m u l t a n e o u s l y , and t y p i c a l r e s u l t s a r e shown i n F i g u r e 13.  I t can be seen t h a t each and e v e r y n e g a t i v e v o l t a g e p u l s e was r e g i s t e r e d by the c o u n t e r , and t h a t the c o u n t e r i n f a c t counted each i n t e r c e p t i n g bubble once and o n l y once.  (The v o l t a g e waveform f e d t o the o s c i l l o s c o p e  inverted.  was  I n fact the b l i p o c c u r s a t each p o s i t i v e  p u l s e as s t a t e d e a r l i e r i n a d e s c r i p t i o n o f t h e o p e r a t i o n of the c o u n t e r . )  The p h y s i c a l s i z e of the probe t i p was a f a c t o r which s u r e l y i n f l u e n c e d the measurements t o some e x t e n t , but was one which c o u l d n o t p r a c t i c a l l y be improved.  It  i s expected t h a t b u b b l e s i n t h e s i z e range o f 0.1 cm. o r l e s s were p r o b a b l y d e f l e c t e d .  F i g u r e 13.  O s c i l l o s c o p e t r a c e s showing v o l t a g e p u l s e s caused by bubbles p a s s i n g the p r o b e - t i p , w i t h c o r r e s p o n d i n g c o u n t e r - b l i p s above.  53  3.1.7  S t a t i s t i c a l E v a l u a t i o n of Data R e p r o d u c e a b i l i t y . Since a l l the measurements were time-averages  f l u c t u a t i n g p o i n t v a l u e s i t was statistical  necessary t o t e s t the  accuracy and r e p r o d u c e a b i l i t y of the r e s u l t s .  The r e s u l t s of such t e s t s are summarized i n Table I. the i n t e g r a t o r readings readings  of  (percent a i r ) and the counter  (bubbles per second) were e v a l u a t e d a t t h r e e  d i f f e r e n t count r a t e s , chosen t o r e p r e s e n t the a c t u a l l y encountered  d u r i n g experimental runs.  range The  sampling accuracy i s good w i t h the standard d e v i a t i o n being low and approximately c o n s t a n t .  Both  54  MEAN VALUE  BUBBLES PER SECOND HIGH COUNT RATE MEDIUM COUNT RATE LOW COUNT RATE  S  (S)  -  80 21 7  0.5 1.2 i.i  1% 6% 16%  75 16 4  3.4 1.1 0.8  5% 7% 20%  (X)  % AIR HIGH COUNT RATE MEDIUM COUNT RATE LOW COUNT RATE  STANDARD DEVIATION  each v a l u e i s based on a sample s i z e o f 50 t e s t s  TABLE I . STATISTICAL EVALUATION OF SAMPLING ACCURACY.  55  3.2 3.2.1  A i r J e t s I n j e c t e d H o r i z o n t a l l y I n t o Water P h y s i c a l Apparatus  The tank used f o r t h i s work was a r e c t a n g u l a r p l e x i g l a s s v e s s e l , 43 cm. x 35 cm. x 50 cm.  deep.  H o r i z o n t a l , s t r a i g h t - b o r e , s t a i n l e s s s t e e l t u y e r e s were c e n t r a l l y l o c a t e d t h r o u g h t h e narrow s i d e w a l l , a t l e a s t 10 cm. above t h e tank bottom.  The a i r s u p p l y was  by  compressed a i r c y l i n d e r s and once a g a i n t h e f l o w was m o n i t o r e d by a r o t a m e t e r , s y m m e t r i c a l l y f l a n k e d by p r e s s u r e gauges.  3.2.2  Elapsed-Time Photography  Time exposures ( u s u a l l y 5s..prl2s.) of t h e gas j e t i n water were t a k e n w i t h a p l a t e camera f o r a v a r i e t y of o p e r a t i n g c o n d i t i o n s .  The b a t h was  illumin-  a t e d by r e f l e c t e d b a c k - l i g h t i n g .  As a r e s u l t t h e  photographed j e t appeared dark a g a i n s t a l i g h t background.  Both the i n i t i a l cone a n g l e and the envelope  of the j e t were measured.  In these t e s t s the j e t  t r a j e c t o r y was assumed t o be the g e o m e t r i c c e n t r e o f the j e t and was c a l c u l a t e d i n each case from the measured e n v e l o p e .  56  I t was  suspected t h a t elapsed-time  might be a more f l e x i b l e measuring i n d i c a t e d by other workers. a j e t was  photographed  photography  d e v i c e than p r e v i o u s l y  To t e s t t h i s  possibility  over a range of exposure  times  a t v a r i o u s l e n s s e t t i n g s , and each n e g a t i v e was  printed  over a range o f exposure times a t v a r i o u s l e n s  settings.  The appearance  o f the j e t was  compared over the range  of photographic and p r i n t i n g c o n d i t i o n s . of o b t a i n i n g data, a good p r i n t was  (For the  purposes  c o n s i d e r e d t o be t h a t  which maximized the apparent s i z e of the j e t envelope but yet maintained sharp c o n t r a s t d e f i n i t i o n between the j e t and the background.  For a given l i g h t i n g  con-  f i g u r a t i o n , the photographic and p r i n t i n g c o n d i t i o n s necessary t o  3.2.3  meet these c r i t e r i a were constant.)  J e t Determination by E l e c t r o r e s i s t i v i t y Probe  H o r i z o n t a l a i r j e t s i n water were measured by means of an e l e c t r o r e s i s t i v i t y probe l a r g e l y f o r the purpose of comparison  with photographic measurements.  I n i t i a l l y , problems were encountered  i n making the water  e l e c t r i c a l l y - c o n d u c t i n g while e l i m i n a t i n g electrode reactions which tended t o i n s u l a t e the exposed s o l u t i o n was than 0.1%)  probe t i p .  The  found i n adding very s m a l l amounts (to l e s s  of HNO^  t o de-ionized and f i l t e r e d water,  u s i n g copper-tipped probes.  while  57  As i n t h e mercury t e s t s t h e moveable probe was mounted on a 3 - d i m e n s i o n a l  o r t h o g o n a l t r a v e r s i n g system  which was g r a d u a t e d t o enable t h e c o - o r d i n a t e  position  of t h e probe i n t h e b a t h t o be read a t any p o i n t .  In  t h i s c a s e , however, t h e e l e c t r o n i c a p p a r a t u s was not as s o p h i s t i c a t e d as t h a t used i n t h e mercury work.  The  average c u r r e n t a t each p o s i t i o n was d e t e r m i n e d by means o f a m i l l i v o l t m e t e r connected a c r o s s a known r e s i s t o r placed i n s e r i e s w i t h the probes.  The o u t p u t from t h e  m i l l i v o l t m e t e r was damped t h r o u g h  an RC c i r c u i t w i t h a  time-constant  of approximately  to a chart recorder.  2 seconds and t h e n f e d  The r e c o r d e r t r a c e was i n t e g r a t e d  over a 20-second time-span f o r each probe p o s i t i o n , and was compared t o t h e " c l o s e d - c i r c u i t " r e a d i n g  obtained  when t h e moveable probe was o u t s i d e t h e j e t  envelope.  T h i s r e f e r e n c e v a l u e was rechecked  many t i m e s  during  each r u n t o ensure c o n s t a n t o p e r a t i n g c o n d i t i o n s .  The  t r a j e c t o r y o f maximum volume f r a c t i o n gas was  determined as t h e l o c u s o f p o i n t s h a v i n g t h e l o w e s t average current readings  (as measured by t h e m i l l i v o l t m e t e r ) .  envelope o f t h e j e t was determined by c u r r e n t  The  readings  w i t h i n one p e r c e n t o f t h e " c l o s e d - c i r c u i t " r e f e r e n c e v a l u e .  58  3.2.4  High-speed C i n e m a t i c Photography  Submerged a i r j e t s i n j e c t e d h o r i z o n t a l l y  into  w a t e r were photographed a t a f i l m speed o f 250 frames p e r second by means o f a Hycam h i g h - s p e e d camera.  Blowing  c o n d i t i o n s were v a r i e d t o c o v e r a range o f m o d i f i e d Froude 2  numbers from 5 x 10 d i a m e t e r o f 0.3 3.2.5  3  t o 6 x 10  at a constant nozzle  cm.  S l u g - f l o w Measurements  S t i l l photographs o f a i r j e t s i n w a t e r  ( F i g u r e 14)  r e v e a l e d the presence of l a r g e bubbles which rose prematurely, outside the j e t envelope.  Since these l a r g e bubbles o r  " s l u g s " would r e d u c e , i n e f f e c t , t h e volume f l o w r a t e o f gas i n t h e main j e t and c o u l d s i g n i f i c a n t l y l o w e r t h e gas u t i l i z a t i o n e f f i c i e n c y of j e t s i n processes i n v o l v i n g gasl i q u i d mass t r a n s f e r , i t was d e c i d e d t o t r y t o measure t h e f r a c t i o n o f t h e gas f l o w w h i c h i s s p e n t i n s l u g  formation.  C a t c h boxes, open a t t h e bottom and w i t h a f l o w m e t e r p o s i t i o n e d on t h e t o p e x i t  h o l e ( F i g u r e 15) were submerged  about one o r two c e n t i m e t e r s i n t h e w a t e r and p o s i t i o n e d a c r o s s t h e tank i n a g r i d sequence.  ( F i g u r e 15a).  Figure  14.  S t i l l photograph of an a i r j e t i n water (Re= 38,400) showing s l u g s .  F i g u r e 15.  Photograph o f a " c a t c h box" used i n t h e measurement of s l u g f l o w .  61  intersection of jet envelope with water surface water surface  tank boundary  grid interval corresponding to catch - box position  F i g u r e 15a. I l l u s t r a t i o n o f catch-box placement i n t h e measurement o f t h e s l u g - f l o w .  62  I t was hoped t h a t i n t h i s manner r e l a t i v e gas flow r a t e s l e a v i n g the d i f f e r e n t s e c t o r s of the tank c o u l d be e s t a b l i s h e d , g i v i n g an i n d i c a t i o n of the f r a c t i o n of t o t a l gas flow which l a y o u t s i d e the main envelope.  63  CHAPTER 4 RESULTS  4.1  Submerged H o r i z o n t a l A i r J e t s i n Mercury  A l l d a t a d e r i v e d from t h e a i r - m e r c u r y system were o b t a i n e d by sampling v a r i o u s p o i n t s w i t h i n t h e b a t h by means o f t h e e l e c t r o r e s i s t i v i t y probe.  A t y p i c a l probe  t r a c e a c r o s s t h e j e t y i e l d e d a gas c o n c e n t r a t i o n p r o f i l e and a bubble f r e q u e n c y p r o f i l e s i m i l a r t o t h o s e i n F i g u r e s 16 and 17.  A one-dimensional  illustrated  t r a c e such as  t h i s , however, i s o f s i g n i f i c a n t v a l u e o n l y when i t passes through t h e c e n t e r l i n e o r t r a j e c t o r y o f t h e j e t .  S i n c e an  aim o f t h i s " w o r k was t o c o m p l e t e l y d e s c r i b e t h e gas d i s t r i b u t i o n a t a l l p o i n t s i n t h e j e t , i t was thought t h a t t h e d a t a c o u l d b e s t be r e p r e s e n t e d as a s e r i e s o f c o n t o u r p l o t s on m u t u a l l y o r t h o g o n a l p l a n e s .  A complete d e s c r i p t i o n o f t h e gas d i s t r i b u t i o n w i t h i n an a i r j e t i n j e c t e d h o r i z o n t a l l y i n t o mercury was attempted  a t four sets of operating c o n d i t i o n s  d e s c r i b e d i n Table I I . The gas volume f r a c t i o n and bubble f r e q u e n c y d i s t r i b u t i o n s were d i r e c t l y measured a t 2000 t o  PROBE  F i g u r e 16.  POSITION  ( cm )  Probe t r a c e through an a i r - m e r c u r y j e t showing gas d i s t r i b u t i o n p r o f i l e .  65  F i g u r e 17.  Probe t r a c e through an air-mercury j e t showing bubble frequency p r o f i l e .  Run No.  Np  HG 4  20.3  0.476  0.29  HG 2  20.3  0.325  0.23  HG 1  105  0.325  0.53  HG 3  288  0.325  0.87  r  do (cm.)  u  Q  (Mach.)  TABLE I I . O p e r a t i n g c o n d i t i o n s t e s t e d i n t h e a i r - m e r c u r y system.  67  3000 d a t a p o i n t s d i s t r i b u t e d throughout the e n t i r e volume of t h e j e t . These p o i n t s were chosen t o l i e on a 3-dimens i o n a l g r i d o f h o r i z o n t a l and v e r t i c a l p l a n e s , s c h e m a t i c a l l y i l l u s t r a t e d i n F i g u r e 18.  The n o z z l e e x i t was  located at  c o o r d i n a t e s (0,0,0) and the p l a n e s were l a b e l l e d a c c o r d i n g t o t h e i r d i s t a n c e from the n o z z l e e x i t , 18.  as shown i n F i g u r e  A computer was programmed t o a c c e p t the d a t a and t o  produce a c o n t o u r map  of the d a t a v a l u e s on each p l a n e .  T h i s program i s l i s t e d i n Appendix I I .  4.1.1  V o l u m e t r i c Gas D i s t r i b u t i o n W i t h i n t h e J e t  A t y p i c a l c o n t o u r map  of volume p e r c e n t a i r ,  o b t a i n e d by the procedure o u t l i n e d e a r l i e r , i s shown f o r a h o r i z o n t a l plane  (B - plane) i n F i g u r e 19.  The  plane  which i s i l l u s t r a t e d i s 2 = 1.3, the h o r i z o n t a l p l a n e l y i n g 1.3. cm.above the t u y e r e c e n t e r l i n e from Run  HG1.  The c o n t o u r v a l u e s range from 70 volume p e r c e n t a i r near the c e n t e r t o the 1 p e r c e n t a i r c o n t o u r which was  chosen  t o d e f i n e t h e o u t e r boundary o f t h e j e t .  F i g u r e 20 i l l u s t r a t e s the c o n t o u r map  of a  v e r t i c a l p l a n e f o r the same o p e r a t i n g c o n d i t i o n s as i n F i g u r e 19  (Run HG 1 ) .  I n t h i s case t h e p l a n e i s X=0,  F i g u r e 19.  Contour nap of volume p e r c e n t a i r f o r the p l a n e 3 = 1.3 of run HG 1.  Figure  20.  C o n t o u r map o f v o l u m e p e r c e n t plane X = 0 o f r u n HG 1.  air for  the  71  the p l a n e p a r a l l e l t o and b i s e c t i n g  the tuyere.  Contour  v a l u e s range from 80 p e r c e n t a i r near t h e n o z z l e e x i t to 1 p e r c e n t a i r a t t h e o u t e r boundary.  The p o s i t i o n  of t h e t u y e r e has been i l l u s t r a t e d on t h e map, and t h e jet trajectory,  r e p r e s e n t e d by a b o l d l i n e , has been  drawn t h r o u g h t h e p o i n t s c o r r e s p o n d i n g t o maximum gas concentration.  F i g u r e s 21 t o 26 i l l u s t r a t e t h e c o r r e s p o n d i n g c o n t o u r maps o b t a i n e d a t t h e o p e r a t i n g c o n d i t i o n s o f runs Hg 2, 3, and 4. j e t s , a complete  To g i v e a f u l l p i c t u r e o f one o f t h e  s e t o f volume p e r c e n t a i r c o n t o u r maps  f o r r u n Hg 1 i s g i v e n i n Appendix I I I .  4.1.2  Bubble Frequency  Distribution  F i g u r e s 27 and 28 show t h e c o n t o u r maps o f bubble frequency f o r r u n Hg 1 on t h e same p l a n e s (& = 1.3 and X=0) as chosen t o i l l u s t r a t e t h e gas d i s t r i b u t i o n .  The bubble  f r e q u e n c i e s range from 1 a t t h e j e t envelope t o g r e a t e r than 100 bubbles p e r second i n t h e c o r e .  F i g u r e s 29  through 34 s i m i l a r l y show t h e bubble f r e q u e n c y measured i n runs Hg 2, 3 and 4.  A complete  distribution  s e t o f bubble  frequency c o n t o u r maps f o r r u n Hg 1 i s i n c l u d e d , as Appendix IV.  o 3  Figure  22.  C o n t o u r map o f volume p e r c e n t p l a n e X = 0 o f r u n HG 2.  a i r for  the  HORIZONTAL  -S.D  -4.0 _l  1L  -3.0 I  -2.D I  DISTANCE  -J.D 1  PERPEND ICULRR 0.0  1.0  1  1  TO N O Z Z L E  2.0 ——•—I  IN  CM  3.0 L.  4.0  i_  5.0  Run HG 4 Volume  %  Air  N'  = 203  d  - 0.476 cm  Fr  0  F i g u r e 25. Contour map o f volume p e r c e n t a i r f o r t h e plane 1.3 o f r u n HG 4. St  =  ON  F i g u r e 26.  Contour map of volume p e r c e n t a i r f o r the p l a n e X = 0 o f run HG 4.  " i • i  F i g u r e 27.  i-!.3  Run HG I  Bubbles  Per Second  N'fr  = 105  d„  = 0325  . cm  L  Contour map of bubble frequency f o r t h e p l a n e % = 1.3 o f r u n HG 1. oo  Run HG I  Bubbles Per Second  ' ,  _  d„  = 0.325 cm  1  Q  5  F i g u r e 28. Contour map o f bubble frequency f o r t h e plane X = 0 o f r u n HG 1.  Figure  29.  Contour B = 1.3  map of bubble o f r u n HG 2.  frequency  f o r the  plane  r»-| -5 0  F i g u r e 30.  , -4.0  , -3.0  , -'-!.0  •-  1  -1.0  , 0.0  , 1.0  , 2.0  . 3.3  HORIZONTAL DtSTflNCt PflFMU.a TO N3Z7.LE IX CM.  1  4.0  •  ! 5.0  •  5.0  Contour map o f bubble frequency f o r t h e p l a n e X = 0 o f r u n HG 2.  f7.0  Run  Z - l .3  HG 3  Bubbles  Per Second  Nrv =288 d =0-325 cm 0  -3.0  1 -2.0  1 -1.0  1 0.0  1 1.0 HORIZONTAL  F i g u r e 31.  1 2.0 DISTANCE  1  1  3.0  4.0  PARALLEL  TO NOZZLE  1 5.0 IN  1 6.0 CM.  Contour map of bubble frequency f o r the plane 3 = 1.3 o f run HG 3.  1 7.0  1— 8.0  igure 33.  Contour map of bubble frequency f o r the plane g = 1.3 o f run HG 4.  F i g u r e 34.  Contour map of bubble f r e q u e n c y f o r the p l a n e X = 0 o f run HG 4.  00  86  4.1.3  V e l o c i t y Measurements /  As d e s c r i b e d e a r l i e r i n the t e x t , v e l o c i t y measurements were attempted i n v a r i o u s r e g i o n s of the jet.  The  i n t e n t was  t h a t a v e l o c i t y map  c o u l d be drawn  and t h a t t h i s i n f o r m a t i o n , combined w i t h t h e c o n c e n t r a t i o n and bubble frequency  gas  d a t a measured  e a r l i e r , would a l l o w the c a l c u l a t i o n of bubble s i z e s throughout the j e t .  These measurements, however, have  not l i v e d up t o e x p e c t a t i o n s as t h e i r a c c u r a c y r e p r o d u c e a b i l i t y were not c o n s i d e r e d t o be  4.1.4  and  satisfactory.  Measurements of Mercury B a c k f l o w into the Tuyere  Mercury b a c k f l o w was  not d e t e c t e d i n t h e  by the e x p e r i m e n t a l method d e s c r i b e d e a r l i e r .  tuyere  The  weak-  ness of the method r e s t e d i n the f a c t t h a t w h i l e d e t e c t i o n p o s i t i v e l y i n d i c a t e d the presence of mercury i n the  tuyere  (barring e l e c t r o n i c malfunction or s h o r t - c i r c u i t ) , l a c k of d e t e c t i o n would not d e f i n i t e l y prove the absence of mercury.  The  f a c t t h a t mercury was  the f o l l o w i n g p o s s i b i l i t i e s :  not d e t e c t e d  allows  87  (i)  When t h e t e s t e l e c t r o d e s were one n i c k e l  w i r e and t h e tank w a l l , mercury s p l a s h e d back i n t o t h e t u y e r e as a d i s c o n t i n u o u s phase.  Thus t h e e l e c t r o d e s  were n o t c o u p l e d and t h e r e was no d e t e c t i o n . (ii)  When t h e t e s t e l e c t r o d e s were two n i c k e l  w i r e s , mercury may have p e n e t r a t e d t h e t u y e r e b u t d i d not c o n t a c t b o t h w i r e s s i m u l t a n e o u s l y . (iii)  Mercury p e n e t r a t e d t h e t u y e r e b u t f e l l  short  of c o n t a c t i n g e i t h e r o f t h e n i c k e l w i r e s . (iv)  Mercury d i d n o t f l o w back i n t o t h e t u y e r e ;  p o s s i b l y because t h e t u y e r e diameter was t o o s m a l l t o a l l o w s i g n i f i c a n t b a c k f l o w , o r p o s s i b l y because a s i t u a t i o n t o encourage b a c k f l o w d i d n o t e x i s t .  4.2  Submerged H o r i z o n t a l A i r J e t s i n Water  The a i r - w a t e r system was s t u d i e d p r i m a r i l y as a backup t o t h e a i r - m e r c u r y work.  Many o f t h e t e s t s done  i n water were f o r t h e purpose o f t e s t i n g e i t h e r used i n t h i s work o r t e c h n i q u e s used by o t h e r  techniques  investigators.  To a c e r t a i n e x t e n t t h e a i r - w a t e r s t u d i e s s e r v e d as a bridge between t h e a i r - m e r c u r y work r e p o r t e d here and p r e v i o u s work done by o t h e r s , who u s u a l l y s t u d i e d t h e a i r - w a t e r o r o t h e r photographable  systems.  In addition, .  88  advantage was t a k e n of the f a c t t h a t an a i r j e t i n water i s v i s i b l e , and i n some cases ( i . e . h i g h - s p e e d c i n e m a t i c photography)  t h e water model was  looked at  t o p r o v i d e i n f o r m a t i o n which was e i t h e r u n o b t a i n a b l e or  l e s s r e a d i l y i n t e r p r e t a b l e t h r o u g h t h e mercury  4.2.1.  Elapsed-Time  tests.  Photography  The t e c h n i q u e of e l a p s e d - t i m e photography  has  been used by o t h e r s , n o t a b l y by Themelis e t a l ( 7 4 ) , t o d e t e r m i n e the envelope o f a submerged a i r - j e t i n water.  T e s t s were conducted on t h e photography  of  h o r i z o n t a l a i r j e t s i n water which show t h a t one s h o u l d be c a u t i o u s i n i n t e r p r e t i n g such i n f o r m a t i o n . 35 i l l u s t r a t e s why.  Figure  The a v a i l a b l e r e s o l u t i o n , which i s  determined by b o t h p h o t o g r a p h i c and p r i n t i n g c o n d i t i o n s , a r b i t r a r i l y d e f i n e s t h e placement o f the j e t envelope  —  whether i t w i l l c o r r e s p o n d , say, t o 1 p e r c e n t a i r o r t o 10 p e r c e n t a i r .  The p i c t u r e s i n F i g u r e 35 show the  i n c o n s i s t e n c y p o s s i b l e through p r i n t i n g c o n d i t i o n s a l o n e . Both p r i n t s a r e from t h e same n e g a t i v e — exposure was changed. the  o n l y the p r i n t i n g  S i m i l a r r e s u l t s c o u l d be shown f o r  case of d i f f e r e n t p h o t o g r a p h i c c o n d i t i o n s b u t  printing conditions.  identical  I t i s noteworthy t h a t such r e s o l u t i o n  d i f f e r e n c e s do n o t , i n the case of h o r i z o n t a l l y - i n j e c t e d  i  F i g u r e 35.  E l a p s e d - t i m e p h o t o g r a p h o f a submerged a i r j e t i n water. Two p i c t u r e s o f t h e same p h o t o graph p r i n t e d under d i f f e r e n t c o n d i t i o n s t o show t h e e x t e n t o f p o s s i b l e v a r i a t i o n i n envelope s i z e .  90  jets,  expand  or c o n t r a c t the envelope s y m m e t r i c a l l y .  If  one were t o d e f i n e the j e t t r a j e c t o r y as the geometric center of the envelope  (as i s commonly done), the  t r a j e c t o r i e s determined from the two p i c t u r e s of F i g u r e s 35 would d i f f e r  considerably.  In t h i s work the photographic c o n d i t i o n s used f o r measurement purposes were always such as t o o b t a i n the maximum-size envelope t h a t s t i l l maintained a dense, dark shade a g a i n s t a b r i g h t  4.2.2  background.  T r a j e c t o r y Determination by Probe and  Air  Photography  j e t s i n water were sampled by an e l e c t r o -  , r e s i s t i v i t y probe i n a manner s i m i l a r t o t h a t used i n the  air-mercury system.  data was  In the water t e s t s , however, the  o b t a i n e d from a m i l l i v o l t m e t e r p l a c e d a c r o s s  a known r e s i s t a n c e i n the probe c i r c u i t .  The  millivolt  readings were normalized such t h a t a r e a d i n g of 100 i n d i c a t e d t h a t the probe as i n c o n t a c t w i t h water w h i l e a reading of 0 i n d i c a t e d t h a t the probe t i p was completely surrounded by a i r .  Although the m i l l i v o l t v a l u e s cannot  be assumed t o d i r e c t l y r e p r e s e n t volume percent l i q u i d phase they are however i n d i c a t i v e , i n t h a t a lower r e a d i n g  91  would c o r r e s p o n d t o a h i g h e r p e r c e n t a g e of g a s .  A  t y p i c a l probe t r a c e through a h o r i z o n t a l a i r j e t i n water i s shown i n F i g u r e 36.  The t r a j e c t o r y o f a submerged h o r i z o n t a l a i r j e t i n water was determined i n two ways:  1.  A time-lapse  photograph o f t h e j e t was t a k e n  and t h e t r a j e c t o r y was c o n s i d e r e d t o be t h e c e n t e r o f t h e envelope. 2.  The d a t a o b t a i n e d from t h e e l e c t r o r e s i s t i v i t y  probe ( a t more than 500 d a t a p o i n t s p e r run) was e v a l u a t e d and t h e t r a j e c t o r y was drawn t h r o u g h t h e p o i n t s o f h i g h e s t gas f r a c t i o n .  The r e s u l t s from b o t h o f t h e s e methods i  are p r e s e n t e d f o r runs a t N_ Fr i n F i g u r e s 37 and 38. 4.2.3  i  = 1500 and N „ = 6700 Fr  Observations of J e t P u l s a t i o n  The p u l s a t i n g b e h a v i o u r of an a i r j e t i n water was observed by means of high-speed c i n e m a t i c photography. F i g u r e 39 i l l u s t r a t e s a t y p i c a l p u l s e c y c l e observed on a s e r i e s of frames from such a high-speed f i l m .  0 >  e  20 o  .? 40 TD  O CD  <T  60  o  a3 £ i 80 > 100  o  -2  -I Probe  gure 36.  I  0 Position  (cm.)  Probe t r a c e t h r o u g h an a i r - w a t e r j e t .  o  Measured Envelope By Photography  a  Measured Trajectory By Probe  10  9  8  > £ o c a to to  bi  2  N  a c  g  0  to c <u  Liquid Surface @ Z = l3lcm.  E -2  b j  0  L  _L  J  L  6  8  Dimensional F i g u r e 37.  10 X-Distance  12  L  14  J  I  16  (cm.) (Horizontal)  The envelope and t r a j e c t o r y of an a i r - w a t e r j e t as . determined by photography and probe. N/ = 1 5 0 0 . Fr  I  18  L  20  O  Measured Envelope By Photography  o  Measured Trajectory By Probe  Liquid Surface @ Z = I3 I cm. I  0  l  I  2  l  I  4  I  6  I  l  8  l  I  10  Dimensional  I  I  12  I  I  14  1  I  I  16  -  6700.  1  18  X-Distance (cm.) (Horizontal)  F i g u r e 38. The envelope and t r a j e c t o r y o f an a i r - w a t e r j e t as determined by photography and probe. Fr  I  I  20  I  I  22  I  I  24  L  t-O.OlOs. F i g u r e 39.  t=0.021s.  A sequence o f frames showing one complete p u l s a t i o n o f an a i r j e t i n w a t e r .  96  - A submerged gas j e t i n a l i q u i d i s n o t a c o n t i n o u s , smoothly f l o w i n g stream b u t r a t h e r i s m a r k e d l y d i s c o n t i n o u s having a v i o l e n t l y p u l s a t i n g nature.  The a i r emerging  from t h e n o z z l e appears t o b u i l d i n t o a l a r g e p u f f w h i c h t h e n b r e a k s up i n t o s m a l l e r b u b b l e s .  These e v e n t s r e p e a t  t h e m s e l v e s r a p i d l y and i r r e g u l a r l y , and i t i s p o s s i b l e t h a t some a s p e c t s o f j e t b e h a v i o u r might be a n t i c i p a t e d from a knowledge o f p u l s a t i o n f r e q u e n c y o r a m p l i t u d e .  4.2.4  Observations of Slugging Behaviour  I t has been o b s e r v e d i n t h e c a s e o f h o r i z o n t a l l y i n j e c t e d j e t s t h a t t h e r e i s a"tendency  f o r large bubbles  o r s l u g s t o r i s e p r e m a t u r e l y o f t h e main e n v e l o p e o f b u b b l e F i g u r e 14 i s a s t i l l photo showing t h e l o c a t i o n o f a s l u g o u t s i d e t h e j e t e n v e l o p e , w h i l e F i g u r e 40 i l l u s t r a t e s , i n a s e r i e s o f frames from a h i g h - s p e e d f i l m , t h e development o f such a s l u g .  The a t t e m p t e d measurement o f gas f r a c t i o n l o s t t o s l u g g i n g was u n s u c c e s s f u l .  The catch-box t e c h n i q u e c o u l d  n o t be made t o work because t h e gas e n t r a i n e d i n t h e l i q u i d was c a r r i e d back o u t o f t h e c a t c h - b o x i n t h e l i q u i d ( F i g u r e 4 1 ) . V a r i o u s arrangements  stream  o f s o l i d and/or w i r e  s c r e e n b a f f l e s were f i t t e d t o t h e c a t c h - b o x e s i n an a t t e m p t t o r e l e a s e t h e e n t r a i n e d g a s . None was s u c c e s s f u l .  t = 0.078s. F i g u r e 40.  A sequence o f frames showing t h e development of a s l u g .  t =  0.091s.  98  To flow meter  jn |-— Catch - box  Liquid leaving with Liquid entering with entrained gas  F i g u r e 41.  entrained gas  I l l u s t r a t i o n of the flow pattern i n the c a t c h box.  99  CHAPTER 5 DISCUSSION  5.1  General D e s c r i p t i o n o f a H o r i z o n t a l l y - I n j e c t e d Gas J e t i n Mercury  S i n c e submerged gas j e t s i n l i q u i d m e t a l s have not p r e v i o u s l y been observed  i n t h e d e t a i l o f f e r e d by  t h i s s t u d y , a g e n e r a l d e s c r i p t i o n o f an a i r j e t i n mercury w i l l be p r e s e n t e d here.  In i t s general features,  Run HG1 i s t y p i c a l o f a l l j e t s s t u d i e d i n t h e a i r - m e r c u r y system, and v a r i o u s c o n t o u r maps from t h i s r u n w i l l be r e f e r r e d t o f o r purposes o f i l l u s t r a t i o n .  The h o r i z o n t a l c o n t o u r maps o f gas d i s t r i b u t i o n and bubble f r e q u e n c y , i l l u s t r a t e d f o r Run HGl i n F i g u r e s 19 and 27 r e s p e c t i v e l y , show c l e a r l y t h a t t h e j e t c o n s i s t s of a c o r e o f h i g h gas c o n c e n t r a t i o n and h i g h bubble frequency which g r a d u a l l y decrease  i n v a l u e toward t h e  edge o f t h e j e t . A t t h e c r o s s - s e c t i o n i l l u s t r a t e d i n these f i g u r e s the j e t i s r i s i n g n e a r - v e r t i c a l l y y e t i t i s not symmetrical, but apparently elongated i n a f o r e and-aft  direction.  100  The v e r t i c a l c o n t o u r map o f gas d i s t r i b u t i o n i l l u s t r a t e d i n F i g u r e 20 i s p a r t i c u l a r l y i m p o r t a n t as i t c o n t a i n s much o f t h e new i n f o r m a t i o n which has been obtained i n t h i s study.  The f i r s t a s p e c t t o be noted i s t h a t  t h e j e t expands v e r y r a p i d l y , i m m e d i a t e l y upon l e a v i n g t h e nozzle.  T h i s i s an unexpected  r e s u l t based on i n f o r m a t i o n  o b t a i n e d from an e x a m i n a t i o n o f submerged j e t s i n t h e a i r water system where i s i t c u r r e n t l y a c c e p t e d t h a t an a i r j e t expands a t a cone a n g l e o f about 20 degrees.  In the a i r -  mercury system i t would appear t h a t t h e j e t expands a t a much l a r g e r cone a n g l e .  Another i m p o r t a n t f e a t u r e i s t h a t t h e j e t p e n e t r a t e s or expands b e h i n d t h e t u y e r e t o a l a r g e e x t e n t , a g a i n an o c c u r r e n c e t h a t one c o u l d n o t p r e d i c t by o b s e r v i n g o n l y the a i r - w a t e r system.  In f a c t the j e t penetrates rearward  t o such an e x t e n t t h a t i t s t r a j e c t o r y , drawn t h r o u g h t h e p o i n t s o f maximum gas f r a c t i o n , appears t o r i s e almost i m m e d i a t e l y upon l e a v i n g t h e t u y e r e .  vertically  In a l l , the  j e t l o o k s v e r y much as though i t were i n j e c t e d from a v e r t i c a l , r a t h e r than a h o r i z o n t a l n o z z l e .  5.2  Cone Angle  The i n i t i a l e x p a n s i o n a n g l e o r cone a n g l e o f a i r j e t s blown i n t o mercury was measured under each o f t h e  101  experimental conditions.  The w i d t h o f the j e t was  measured b o t h from the c o n t o u r maps and from  independent  probe measurements i n a t r a n s v e r s e d i r e c t i o n , i . e . p e r p e n d i c u l a r t o the d i r e c t i o n o f i n i t i a l i n j e c t i o n the b a t h .  into  I n t h i s manner t h e n a t u r a l e x p a n s i o n of an  air  j e t i n mercury  i s measured.  are  l i s t e d i n Table I I I ,  These r e s u l t s , which  c l e a r l y i l l u s t r a t e how a i r j e t s  i n mercury behave much d i f f e r e n t l y t h a n a i r j e t s i n w a t e r .  The cone a n g l e i s c o n s t a n t a t r o u g h l y 150°  to  155°,  and shows no d i s t i n c t v a r i a t i o n w i t h changes i n e i t h e r m o d i f i e d Froude number o r n o z z l e d i a m e t e r .  This value  i s more t h a n seven t i m e s g r e a t e r t h a n the 20° cone a n g l e which was p r e v i o u s l y thought t o a p p l y t o a l l air  (subsonic)  j e t s r e g a r d l e s s o f the medium i n t o which t h e y were  injected. I  To check t h a t the l a r g e cone a n g l e was not a f u n c t i o n o f tank d e s i g n and caused by p a r t i c u l a r p a t t e r n s i n the b a t h , t h e f o l l o w i n g t e s t was  stirring  conducted.  The c y l i n d r i c a l v e s s e l c o n t a i n i n g t h e mercury was d r a i n e d and f i l l e d w i t h water, and an a i r j e t was b a t h and photographed described e a r l i e r .  i n j e c t e d i n t o the  by t h e e l a p s e d - t i m e t e c h n i q u e  Such a photograph i s shown i n F i g u r e  42 and i l l u s t r a t e s t h a t the a i r j e t i n water expands a t the a n t i c i p a t e d 20° cone a n g l e .  The l a r g e cone a n g l e s  102  Run No.  Fr  Nozzle Diameter (cm.)  Cone* Angle (Degrees)  HG 4  20.3  0.476  157.9 156.6 142.9 146.1  HG 2  20.3  0.325  HG 1  105  0.325  155.9 153.7  HG 3  288  0.325  154.3 155.9  The f i r s t value of each pair i s obtained from the contour: 1% A i r ; The Second value i s from the contour: 1 Bubble Per Second.  TABLE I I I :  JET CONE ANGLES MEASURED AT A HORIZONTAL DISTANCE OF 0.5 cm. FROM THE NOZZLE  103  Figure  42.  Time-lapse photograph of an a i r - w a t e r j e t i n the c y l i n d r i c a l v e s s e l used d u r i n g the a i r - m e r c u r y t e s t s . The cone a n g l e i s  20°.  104  measured i n mercury were t h e r e f o r e a f u n c t i o n o f the a i r - m e r c u r y system and not o f t h e p a r t i c u l a r equipment geometry.  The cone a n g l e was a l s o measured as a f u n c t i o n of t u y e r e submergence, by v a r y i n g t h e depth o f mercury i n the bath.  F i g u r e s 43 and 44 show t h e gas c o n c e n t r a t i o n  p r o f i l e s o b t a i n e d a t r e s p e c t i v e d i s t a n c e s o f 0.3am. and 1.3 c m above t h e t u y e r e e x i t f o r o p e r a t i n g c o n d i t i o n s c o r r e s p o n d i n g t o t h o s e o f Run HG 4.  I n each c a s e ,  r e g a r d l e s s o f t u y e r e submergence d e p t h , t h e  profilesare  i d e n t i c a l and, t h e r e f o r e , t h e cone a n g l e s a r e i d e n t i c a l and do not v a r y w i t h mercury depth over t h e range s t u d i e d .  The range o f submergence d e p t h s s t u d i e d produced a p r e s s u r e change a t t h e o r i f i c e o f o n l y 6 t o 7 p e r c e n t . I t i s p o s s i b l e t h a t i n a s i t u a t i o n where t h e mercuros t a t i c head c o n t r i b u t e d s i g n i f i c a n t l y t o t h e p r e s s u r e o f the system t h e cone a n g l e may be a f f e c t e d by a change i n the t o t a l head.  Distance (cm) I  F i g u r e 43.  J e t w i d t h v s . t u y e r e submergence. T r a v e r s e t a k e n a t 0.3 cm. above the t u y e r e f o r Run HG 4.  o Ui  F i g u r e 44.  J e t w i d t h v s . t u y e r e submergence. T r a v e r s e t a k e n a t 1.3 cm. above the t u y e r e f o r Run HG 4.  §  107  5.3  J e t Diameter  A l t h o u g h t h e cone a n g l e may  be used t o deduce t h e  j e t d i a m e t e r near the t u y e r e , the j e t d i a m e t e r i s s t i l l i m p o r t a n t as an independent parameter  s i n c e the j e t does  not expand a t the o r i g i n a l cone a n g l e over i t s e n t i r e trajectory length.  F i g u r e 45 d e s c r i b e s t h e r e l a t i o n s h i p  between j e t d i a m e t e r and t r a j e c t o r y l e n g t h d e t e r m i n e d b o t h by experiment i n the a i r - m e r c u r y system and by p r e d i c t i o n based on the p r e v i o u s l y a c c e p t e d cone a n g l e of  20°.  V a l u e s o f the j e t d i a m e t e r i n the t h r e e e x p e r i m e n t a l c u r v e s were o b t a i n e d from t h e 1 p e r c e n t a i r c o n t o u r s o f the v a r i o u s h o r i z o n t a l planes.  The d i a m e t e r was measured  i n the t r a n s v e r s e d i r e c t i o n s i n c e , as i n t h e cone a n g l e measurements, i t was thought t h a t t h i s would b e s t r e f l e c t the n a t u r a l e x p a n s i o n o f the j e t . I t can be seen t h a t i n i t i a l l y t h e j e t s expand q u i c k l y and then t e n d t o approach a c o n s t a n t d i a m e t e r and r i s e as a column.  It  appears t h a t the j e t diameter i n c r e a s e s b o t h w i t h i n c r e a s i n g Froude number and o r i f i c e d i a m e t e r and i s , i n t h e a i r mercury  system, v e r y much g r e a t e r t h a n t h a t p r e d i c t e d by  models of c o n t i n o u s expansion  a t a cone a n g l e of  20°.  2  3  4  5  6  7  Distance Along Jet Trajectory , s ,  8  9  (cm)  F i g u r e 45. J e t d i a m e t e r v s . d i s t a n c e a l o n g  trajectory,  o  00  109  5.4  Jet Trajectory  I t was  seen e a r l i e r i n F i g u r e 20 and  c o n t o u r maps ( F i g u r e s 22, 24, and  in similar  26) t h a t t h e t r a j e c t o r y  of an a i r j e t i n mercury becomes v e r t i c a l almost i m m e d i a t e l y a f t e r the j e t e x i t s the t u y e r e .  F i g u r e s 46 t o 49 compare,  f o r each r u n , the t r a j e c t o r y e x p e r i m e n t a l l y by measurements i n the a i r - m e r c u r y  determined  system t o t h o s e w h i c h  would be p r e d i c t e d by the model o f T h e m e l i s e t a l  (74)  u s i n g b o t h t h e p r e v i o u s l y a c c e p t e d cone a n g l e of 20°  and  the e x p e r i m e n t a l l y measured cone a n g l e i n each c a s e .  It  i s o b v i o u s t h a t the model of T h e m e l i s e t a l , when used w i t h a 20° cone a n g l e , does not p r e d i c t the t r a j e c t o r y of an a i r j e t i n mercury, o v e r e s t i m a t i n g  the h o r i z o n t a l  p e n e t r a t i o n by up t o 1500  HG  percent  i n Run  3.  When the  e x p e r i m e n t a l l y determined cone a n g l e i s i n s e r t e d i n each case the model more a c c u r a t e l y p r e d i c t s the measured t r a j e c t o r i e s although  i t tends t o u n d e r e s t i m a t e the  h o r i z o n t a l p e n e t r a t i o n by a s m a l l amount.  lOr  T  1  1  1  1  1  1  N'  Fr  d  0  1  r  T  = 105 = 0.325 cm  8c 20 6 = 155° 155  •- Themelis et ol  C  :  2  3  4 5  Horizontal  — experimental l 6  Distance  l 7  l 8  155 ' 1  9  10  From Nozzle  (cm)  II  12  1-1  F i g u r e 46. Comparison o f e x p e r i m e n t a l and t h e o r e t i c a l t r a j e c t o r i e s f o r Run HG 1.  jet  g  -  IOI— 9  1  T  r  r  T  —  1" 8  S -2  7  = 0.325  cm  ' 6!-  4 1-  /  r i.  Themelis  8 = 20° • 8 -- 145 ° 8 = 145 °"  et al  C  C  experimental J L  0  1  2  Horizontal  3  4  5  Distance  6 From  JL  JL.  7  8  Nozzle  C  9  l  l  10  II  F i g u r e 47. Comparison o f e x p e r i m e n t a l and t h e o r e t i c a l j e t t r a j e c t o r i e s f o r Run HG 2.  12  (cm)  £  10  i  r  r  1  V  9  T  1  r  1  8  d„  7  =0.325 cm  6  5 4 3 2  y  I  Themelis et ol  0 -I  6. = 20 ° G = 155° 9 = 155° c  I  _1_  _1_  2  3  Horizontal  • experimentol  _l_  4  J  5 6  i  C  I  7 8  Distance From Nozzle  9  10  II  12  (cm)  F i g u r e 48. Comparison o f e x p e r i m e n t a l and t h e o r e t i c a l j e t t r a j e c t o r i e s f o r Run HG 3.  i—  1  lOr  e  1 —  1  T  r  T  1  1  N'  8  1  Fr  d„  1  "T  T-  =20.3 = 0.476 cm  o  a  <  /  •-  Themelis et ol ti  II  — _L_  0  1  2  3  Horizontal  F i g u r e 49.  4  5  Distance  7  8  From Nozzle  C  e  8  experimentol 6  9 =20 " -j  9 -- 157 °  II  _1 9  C  I  10  «I57» II  L  12  (cm)  Comparison of experimental and t h e o r e t i c a l j e t t r a j e c t o r i e s f o r Run HG 4.  114  5.5  Jet Penetration  The  p e n e t r a t i o n d i s t a n c e s of both the j e t t r a j e c t o r y  and t h e o u t e r b o u n d a r i e s o r e n v e l o p e o f t h e j e t have been measured i n t h e a i r - m e r c u r y i n T a b l e IV.  system and a r e  Before proceeding  presented  w i t h the d i s c u s s i o n ,  t h e terms used i n t h e t a b l e s h o u l d be c l a r i f i e d .  The  t r a j e c t o r y p e n e t r a t i o n i s the h o r i z o n t a l co-ordinate  of  the j e t t r a j e c t o r y at i t s i n t e r s e c t i o n w i t h , i n t h i s  case,  t h e h o r i z o n t a l p l a n e l o c a t e d 6.3  cm.  above t h e  tuyere.  S i m i l a r l y , t h e f o r w a r d p e n e t r a t i o n i s t h e maximum h o r i z o n t a l d i s t a n c e i n f r o n t of t h e t u y e r e a t w h i c h t h e l e a d i n g edge o f the j e t e n v e l o p e i n t e r s e c t s t h e a = 6.3,  plane  w h i l e the back p e n e t r a t i o n i s t h e h o r i z o n t a l  d i s t a n c e from t h e t u y e r e a t w h i c h t h e r e a r edge o f  the  j e t e n v e l o p e i n t e r s e c t s t h e B = 6.3  inter-  plane.  I f the  s e c t i o n p o i n t l i e s ahead o f t h e n o z z l e , t h e p e n e t r a t i o n value i s p o s i t i v e , i f behind value i s negative.  the n o z z l e , the  penetration  Thus, the b a c k - p e n e t r a t i o n  values i n  T a b l e IV show t h a t the j e t e n v e l o p e extended b e h i n d nozzle a s i g n i f i c a n t d i s t a n c e i n every  The  the  case.  t r a j e c t o r y p e n e t r a t i o n i s seen t o be  constant,  showing no v a r i a t i o n w i t h e i t h e r Froude number o r  tuyere  Trajectory Penetration ( cm. )  Maximum Forward Penetration (cm. )  Maximum Back Penetr; (cm.  Run No.  N iF r  Nozzle Diameter (cm. )  HG 4  20. 3  0.476  0.5  5.5 5.5  -3.3 -3.5  HG 2  20.3  0. 325  0.5  4.4 4.2  -2.5 -3.0  HG 1  105  0. 325  0.5  6.2 6.5  -3.4 -3.5  HG 3  288  0. 325  0.5  6.5 7.5  -2.5 -2.7  * The f i r s t v a l u e o f each p a i r i s o b t a i n e d from the c o n t o u r : The second v a l u e i s from t h e c o n t o u r : TABLE IV:  1% A i r ;  1 Bubble P e r Second.  EXPERIMENTAL JET PENETRATION DISTANCES AT A VERTICAL DISTANCE ABOVE THE NOZZLE OF 6.3 cm.  116  diameter.  The maximum forward p e n e t r a t i o n o f t h e j e t  envelope appears t o i n c r e a s e w i t h Froude number and p o s s i b l y w i t h t u y e r e d i a m e t e r as w e l l b u t no c l e a r t r e n d i s i n d i c a t e d f o r the p e n e t r a t i o n of the rear of the envelope.  T a b l e V compares t h e p e n e t r a t i o n d i s t a n c e s  obtained  e x p e r i m e n t a l l y t o those p r e d i c t e d by t h e model o f T h e m e l i s et a l ( 7 4 ) .  I t can be seen t h a t w i t h t h e cone angle o f  2 0 ° , t h e model g r e a t l y o v e r e s t i m a t e s  the t r a j e c t o r y  p e n e t r a t i o n , as was demonstrated a l s o i n t h e p r e v i o u s section.  Although  t h e maximum f o r w a r d p e n e t r a t i o n i s  r o u g h l y p r e d i c t e d , t h e model i n d i c a t e s t h e r e a r o f t h e envelope t o l i e about as f a r i n f r o n t o f t h e t u y e r e as i t i n f a c t p e n e t r a t e s behind  it.  That t h e model f a i l s  t o p r e d i c t t h e p e n e t r a t i o n o f t h e j e t behind exit  i s an i m p o r t a n t  processes  the tuyere  c o n s i d e r a t i o n when a p p l y i n g i t t o  such as copper c o n v e r t i n g where t h e t u y e r e s  are mounted f l u s h w i t h t h e i n s i d e w a l l o f t h e v e s s e l . When t h e e x p e r i m e n t a l l y - d e t e r m i n e d the model a d e q u a t e l y  cone a n g l e s a r e u s e d ,  r e f l e c t s the actual t r a j e c t o r y  p e n e t r a t i o n but d r a s t i c a l l y underestimates  both the  forward and back p e n e t r a t i o n d i s t a n c e s p r e d i c t i n g , i n e f f e c t , a j e t which i s g r e a t l y underexpanded i n comparison to the r e a l s i t u a t i o n .  T h i s i s because t h e T h e m e l i s model  assumes t h e j e t t o expand as a f u n c t i o n o f i t s h o r i z o n t a l  Run No.  HG4  HG2  HG1  HG3  CONE* ANGLE (degrees)  N' h  r  experimental theoretical theoretical  157 157 20  20.3  experimental theoretical theoretical  NOZZLE DIAMETER (cm.)  TRAJECTORY PENETRATION (cm.)  0.476  H  II  n  II  145 145 20  20.3  0.325  experimental theoretical theoretical experimental theoretical theoretical  II  II  II  II  155 155 20  105  0.325  II  II  n  H  155 155 20  288 n n  0.325 n II  * The experimental 'values are an average o f those 1 Bubble per Second c o n t o u r s .  TA8LE V:  MAXIMUM* FORWARD . PENETRATION (cm.)  MAXIMUM* BACK PENETRATION (cm.)  0.5 0.1 4.0  5.5 0.6 4.9  -3.4 -0.5 +3.1  0.5 0.1 2.9  4.3 0.7 3.6  -2.8 -0.4 +2.3  0.5 0.3 5.2  6.4 1.5 6.3  -3.5 -1.0 +4.1  0.5 0.5 7.2  7.0 2.9 10.1  -2.6 -1.9 +4.3  obtained from both  the 1% a i r  and  COMPARISON OF EXPERIMENTAL AND THEORETICAL JET PENETRATION DISTANCES AT A VERTICAL DISTANCE ABOVE THE NOZZLE OF 6.3 cm.  118  t r a j e c t o r y p e n e t r a t i o n d i s t a n c e and, when t h e c o r r e c t cone a n g l e s a r e i n s e r t e d , t h e t r a j e c t o r y p e n e t r a t e s only a very short d i s t a n c e .  Ishibashi  (83) has developed t h e f o l l o w i n g  expression f o r back-penetration  '(  o f an a i r - j e t i n w a t e r :  16  -a " 5  =  . (5.1) N  Fr  \  where 1 = do = N' = r r Lo =  p e n e t r a t i o n d i s t a n c e behind nozzle diameter m o d i f i e d Froude number n o z z l e submergence depth  the nozzle  That t h e r e l a t i o n s h i p was developed from work i n t h e a i r water system i n d i c a t e s t h a t t h e b a c k - p e n e t r a t i o n r e f e r r e d t o by I s h i b a s h i may w e l l be t h a t due t o s l u g f o r m a t i o n . When a p p l i e d t o t h e a i r - m e r c u r y g r e a t l y underestimates penetration.  system, e q u a t i o n  5.1  t h e degree o f measured back-  119  5.6  5.6.1  O r i g i n s o f J e t Behaviour  J e t Pulsations  There i s thought t o be a s t r o n g p o s s i b i l i t y  that  the key t o u n d e r s t a n d i n g t h e b e h a v i o u r o f g a s - l i q u i d l i e s i n t h e study o f t h e i r p u l s a t i n g n a t u r e .  jets  High-speed  photographs o f a i r j e t s i n w a t e r , s i m i l a r t o t h e sequence i n F i g u r e 3 9 , sometimes show a complete break i n t h e a i r stream i s s u i n g from t h e n o z z l e .  Were high-speed  photographs  p o s s i b l e i n t h e mercury b a t h t h e y might have i l l u s t r a t e d a complete f l o w r e v e r s a l , w i t h mercury f l o w i n g back i n t o the t u y e r e between p o s i t i v e f o r w a r d p u l s a t i o n s .  The experiments d e s i g n e d t o d e t e c t such a b a c k f l o w i n t o the t u y e r e were u n s u c c e s s f u l , b u t t h e e x i s t e n c e o f t h i s b e h a v i o u r cannot be r u l e d o u t .  A p e r i o d i c rearward  motion o f l i q u i d would e x p l a i n why t h e j e t envelope so f a r b e h i n d t h e t u y e r e —  i n addition to slug-like  bubbles which r i s e v e r t i c a l l y , gas b u b b l e s c o u l d be d e f l e c t e d r e a r w a r d by l i q u i d  extended  flow.  120  5.6.2  P h y s i c a l P r o p e r t i e s of the  Liquid  A l t h o u g h i t has been p r e v i o u s l y thought t h a t p r o p e r t i e s of the ambient f l u i d medium have no  the  effect  upon the e x p a n s i o n b e h a v i o u r of the j e t , i t i s o b v i o u s when comparing the o b s e r v a t i o n s  o f an a i r j e t i n water  t o those of an a i r j e t i n mercury t h a t the p h y s i c a l p r o p e r t i e s of the l i q u i d do a f f e c t the j e t  behaviour.  Which of the f l u i d p r o p e r t i e s i s the most i n t h i s r e g a r d i s s t i l l not c l e a r .  T a b l e VI shows d e n s i t y  and s u r f a c e t e n s i o n t o be the two p r o p e r t i e s w i t h g r e a t e s t v a l u e d i f f e r e n c e between mercury and The  important  the  water.  d e n s i t y of mercury i s about f o u r t e e n t i m e s t h a t of  water w h i l e the s u r f a c e t e n s i o n o f mercury i s g r e a t e r by a p p r o x i m a t e l y  a f a c t o r of seven.  E i t h e r o r b o t h of  these p r o p e r t i e s c o u l d have been r e s p o n s i b l e f o r the s e v e n - f o l d i n c r e a s e i n cone a n g l e e x p e r i e n c e d air-mercury favoured  i n the  system,.although the d e n s i t y has t o be  candidate  the  because of i t s g r e a t e r range.  S p e s i v t s e v e t a l (73) have s t u d i e d t h e i n t e r a c t i o n of gas  j e t s w i t h s e v e r a l l i q u i d s and  d e n s i t y i s the f a c t o r  i n d i c a t e t h a t the  which d e t e r m i n e s the  liquid  penetration  d i s t a n c e o f a gas j e t i n t o the l i q u i d and t h a t w h i l e  the  s u r f a c e t e n s i o n has some i n f l u e n c e , i t i s s m a l l i n comparison t o t h a t of the d e n s i t y .  121  5.7  Extension to I n d u s t r i a l  5.7.1  Systems.  P h y s i c a l P r o p e r t i e s o f the L i q u i d  S i n c e i t i s not c e r t a i n which o f the p h y s i c a l p r o p e r t i e s p l a y t h e dominant r o l e i n d i c t a t i n g t h e j e t c h a r a c t e r i s t i c s , i t i s d i f f i c u l t a t t h i s time t o e x t r a p o l a t e the r e s u l t s o f t h i s work t o m e t a l l u r g i c a l systems o f industrial significance.  T a b l e V I , however, shows t h e  d e n s i t i e s o f l i q u i d copper and l i q u i d i r o n t o l i e r o u g h l y midway between those of water and mercury, and i f t h e l i q u i d d e n s i t y i s the d e t e r m i n i n g f a c t o r i n j e t b e h a v i o u r one might expect the j e t i n a copper c o n v e r t e r o r i n a s t e e l m a k i n g c o n v e r t e r t o expand a t r a t e between t h a t of an a i r j e t i n water and t h a t of an a i r j e t i n mercury.  There i s , however, a f u r t h e r c o m p l i c a t i n g f a c t o r : submerged gas j e t s i n r e a l m e t a l l u r g i c a l p r o c e s s e s comprise n o n - i s o t h e r m a l , r e a c t i v e systems.  The sudden e x p a n s i o n o f  a c o l d gas j e t upon c o n t a c t w i t h a hot m e t a l b a t h o r a s i m i l a r e x p a n s i o n due t o an e x o t h e r m i c r e a c t i o n w i l l  cause  the j e t t o expand and r i s e more r a p i d l y t h a n a n t i c i p a t e d . I t i s p r o b a b l e then t h a t an a i r j e t i n mercury  reflects  f a r more a c c u r a t e l y t h e b e h a v i o u r o f a gas j e t i n a copper c o n v e r t i n g o r s t e e l m a k i n g p r o c e s s . t h a n does an a i r j e t i n water.  AIR (20 C)  WATER (20 C)  DENSITY, P (gm./cm )  -3 1.2 x 10  SURFACE TENSION, a' (dynes/cm)  undefined  VISCOSITY, V (cp)  1.8 x 10-2  1.0  KINEMATIC VISCOSITY v=y/p (cm /sec)  15.2  1.0  3  2  TABLE VI  MERCURY (20°C)  LIQUID COPPER  LIQUID IRON  7.1  1.0  13.6  7.7  73.5  465  800-1300  800-1300  1.6  2.5- 3.5  5.2- 7.0  0.1  0.3-0.5  0.7-1.0  COMPARATIVE PHYSICAL PROPERTIES OF AIR, WATER, MFJ3CURY, LIQUID COPPER, AND LIQUID IRON OR STEEL.  123  5,. 7. 2 .  P h e n o m e n o l o g i c a l Comparison  Although,  as mentioned e a r l i e r , i t i s n o t  p o s s i b l e at t h i s time to d i r e c t l y extend the o f t h i s work t o t h e more c o m p l i c a t e d  results  industrial  systems,  i t i s p o s s i b l e t o examine some i n d u s t r i a l l y - o c c u r r i n g phenomena i n r e l a t i o n t o i d e a s p r e s e n t e d  in this  In p a r t i c u l a r , lance plugging d u r i n g the l a d l e s u l p h u r i z a t i o h of s t e e l  de-  (86) and b o t h t u y e r e e r o s i o n  and b a c k - w a l l e r o s i o n d u r i n g copper c o n v e r t i n g w i l l be  thesis.  (87)  considered.  5.7.2.1  Lance p l u g g i n g i n t h e l a d l e d e s u l p h u r i z a t i o n of s t e e l  S i n c e e a r l y 1973  t h e S t e e l Company o f Canada, L i m i t e d ,  has been d e s u l p h u r i z i n g s m a l l tonnages o f b l a s t i r o n i n torpedo  furnace  l a d l e s by means o f t h e pneumatic i n j e c t i o n  o f powdered magnesium impregnated coke o r v a r i o u s magnesium a l l o y s through  an i n j e c t i o n l a n c e d i r e c t e d downward a t an  a n g l e o f 30° t o the v e r t i c a l  (86).  A t one  stage i n the  development o f t h i s p r o c e d u r e l a n c e p l u g g i n g was problem.  The  photograph  blockages  o c c u r r i n g a t the nose o f t h e l a n c e .  w i t h i n t h e l a n c e was  a serious  o f F i g u r e 50 i l l u s t r a t e s t y p i c a l The  d e t e r m i n e d t o be p r i m a r i l y hot  deposit metal  124  F i g u r e 50.  Photograph i l l u s t r a t i n g lance plugging due t o b a c k f l o w o f l i q u i d s t e e l i n t o a lance. C o u r t e s y o f Wood e t a l (86) .  125  which had been drawn back up the l a n c e p i p e by  virtue  of g a s - l i n e p r e s s u r e f l u c t u a t i o n s which o c c u r r e d d u r i n g injection.  That hot m e t a l was drawn back a s i g n i f i c a n t d i s t a n c e i n t o a v e r t i c a l l a n c e i l l u s t r a t e s not o n l y t h e e x i s t e n c e of b a c k - p e n e t r a t i o n but a l s o the magnitude o f the p u l s a t i o n s o c c u r r i n g i n the j e t . A l t h o u g h not s u c c e s s f u l l y measured in laboratory t e s t s there i s d i r e c t i n d u s t r i a l  proof  t h a t b a c k f l o w does o c c u r i n the t u y e r e and a s t r o n g case i s made f o r the importance  o f s t u d y i n g the p u l s a t i n g  n a t u r e o f submerged gas j e t s i n l i q u i d s .  5.7.2.2.  Tuyere E r o s i o n D u r i n g Copper C o n v e r t i n g  S i m i l a r evidence s u p p o r t i n g the b a c k f l o w o f  liquid  i n t o the t u y e r e i s p r o v i d e d by t h e severe t u y e r e d e t e r i o r a t i o n e x p e r i e n c e d i n copper c o n v e r t i n g (87) .  The  resulting  c o n f i g u r a t i o n of the nose of the t u y e r e suggests r e a c t i o n was  that  t a k i n g p l a c e v e r y c l o s e t o t h e t i p o f the  n o z z l e o r w i t h i n the t u y e r e i t s e l f .  This behaviour i s  a n t i c i p a t e d by the assumption of l i q u i d - m e t a l b a c k f l o w .  126  5.7.2.3  Back-Wall  E r o s i o n I n A Copper C o n v e r t e r  Some o f t h e most severe e r o s i o n problems i n a copper c o n v e r t e r o c c u r on t h e back w a l l o f t h e v e s s e l , immediately above and b e h i n d t h e t u y e r e s .  In the past  t h i s o c c u r r e n c e has n o t been s a t i s f a c t o r i l y e x p l a i n e d . However, if. t h e f i n d i n g s o f t h e p r e s e n t a i r - m e r c u r y s t u d i e s are extended t o t h e l i q u i d copper system one o f t h e s i t u a t i o n s r e a l i z e d i s t h a t , because t h e j e t r i s e s v e r y q u i c k l y and p e n e t r a t e s rearward t o a l a r g e e x t e n t and a l s o because the t u y e r e s o f a copper c o n v e r t e r a r e i n s t a l l e d  flush  w i t h t h e i n s i d e w a l l o f t h e v e s s e l , t h e j e t impinges d i r e c t l y upon t h e w a l l o f t h e c o n v e r t e r i n t h e r e g i o n corresponding t o that of greatest erosion.  When, i n  a d d i t i o n , i t i s remembered t h a t t h e t u y e r e i t s e l f i s b e i n g eroded away by r e a c t i o n w i t h i n t h e n o z z l e and i s r e c e d i n g i n t o t h e c o n v e r t e r w a l l , i t can be a n t i c i p a t e d t h a t t h e e r o s i o n o f t h e c o n v e r t e r w a l l would be as e x t e n s i v e as i s i n f a c t seen t o be t h e c a s e .  S i n c e t h i s w a l l e r o s i o n has n o t been w e l l - e x p l a i n e d p r e v i o u s l y , t h e c o r r e l a t i o n developed p r o v i d e s remarkably  i n t h e above argument  strong c i r c u m s t a n t i a l evidence t h a t the  gas j e t s i n a copper c o n v e r t e r behave s i m i l a r l y t o those o f the a i r - m e r c u r y system i n t h a t they r i s e v e r y q u i c k l y and p e n e t r a t e b e h i n d t h e plane o f t h e n o z z l e e x i t .  127  CHAPTER 6 CONCLUSION 6.1  Summary  (i)  The 3-dimensional d i s t r i b u t i o n s o f gas volume  f r a c t i o n and b u b b l e frequency have been measured w i t h i n a submerged, h o r i z o n t a l l y - i n j e c t e d a i r j e t i n mercury f o r o p e r a t i n g c o n d i t i o n s c o v e r i n g a range o f m o d i f i e d Froude numbers between 20 and 300 and n o z z l e d i a m e t e r s o f 0.325 cm. and 0.47 6 cm. (ii)  The cone a n g l e o f an a i r j e t i n mercury was  found t o be a p p r o x i m a t e l y 150° and was n o t seen t o v a r y s i g n i f i c a n t l y w i t h e i t h e r m o d i f i e d Froude number o r n o z z l e diameter.  T h i s v a l u e i s r o u g h l y 7 t i m e s t h a t measured f o r  an a i r j e t i n water. ( i i i ) . As a consequence o f t h e above, t h e h o r i z o n t a l l y i n j e c t e d a i r j e t i n mercury behaved i n terms o f b o t h , i t s t r a j e c t o r y and f o r w a r d and back p e n e t r a t i o n almost as though i t were i n j e c t e d v e r t i c a l l y upwards. (iv)  The a i r j e t i n mercury does n o t c o n t i n u e  t o expand a t t h e o r i g i n a l cone a n g l e , b u t r i s e s as a column through most o f i t s v e r t i c a l a s c e n t .  128  (v)  A l t h o u g h i t has been p r e v i o u s l y thought t h a t  the p r o p e r t i e s o f t h e ambient f l u i d medium have no e f f e c t upon t h e e x p a n s i o n b e h a v i o u r o f t h e j e t , t h e r e s u l t s o f t h i s work c l e a r l y show t h a t t h e f l u i d p r o p e r t i e s do have a s i g n i f i c a n t e f f e c t on, f o r example, t h e cone a n g l e .  I t i s suggested  t h a t t h e f l u i d d e n s i t y has t h e dominant i n f l u e n c e i n t h i s r e g a r d .  (vi)  I t i s p r o b a b l e t h a t i n d u s t r i a l copper  convert-  i n g and s t e e l m a k i n g s i t u a t i o n s a r e more c l o s e l y r e p r e s e n t e d by t h e a i r - m e r c u r y system then by t h e a i r - w a t e r system. However, t h e n o n - i s o t h e r m a l , r e a c t i v e n a t u r e o f t h e i n d u s t r i a l o p e r a t i o n s r e q u i r e s a c a u t i o u s approach when one attempts e x t r a p o l a t i o n from s i m p l i f i e d e x p e r i m e n t a l  6.2  Suggested  (i) be pursued  systems.  F u t u r e Work  I t i s recommended t h a t n o n - i s o t h e r m a l  experiments  i n p o s s i b l y t h e a r g o n - l e a d o r argon-aluminum systems  t o determine  t h e e f f e c t o f sudden gas e x p a n s i o n due t o h e a t i n g  upon t h e cone a n g l e o f t h e j e t .  (ii)  U t i l i z i n g t h e a i r - w a t e r system, t h e p r e s s u r e  f l u c t u a t i o n s i n t h e a i r - l i n e near t h e t u y e r e s h o u l d be measured and r e l a t e d t o t h e p u l s a t i o n s observed by high-speed  photography.  129  (iii)  S i m i l a r l y , t h e p r e s s u r e p u l s a t i o n s o f an  a i r j e t i n mercury and t h o s e o f a n o n - i s o t h e r m a l g a s - l i q u i d m e t a l system s h o u l d be m o n i t o r e d and r e l a t e d t o o p e r a t i n g c o n d i t i o n s and t o phenomena o c c u r r i n g w i t h i n the b a t h , k e e p i n g i n mind the p o s s i b i l i t y o f d e v i s i n g a s u i t a b l e m o n i t o r i n g system f o r i n d u s t r i a l p r o c e s s c o n t r o l .  (iv)  I n g e n e r a l , work i s n e c e s s a r y t o i s o l a t e  the r e l a t i v e i n f l u e n c e s upon j e t b e h a v i o u r h e l d by t h e d e n s i t y , v i s c o s i t y and s u r f a c e t e n s i o n o f t h e  liquid.  APPENDIX I CIRCUIT DIAGRAMS  C i r c u i t diagrams of t h e e l e c t r o n i a p p a r a t u s used i n c o n j u n c t i o n w i t h t h e e l e c t r o r e s i s t i v i t y probe d u r i n g t h e a i r mercury e x p e r i m e n t s .  131  F i g u r e 51.  C i r c u i t diagram o f t h e i n t e g r a t o r used i n t h e a i r - m e r c u r y experiments t o measure gas volume f r a c t i o n .  132  166 C12  117 V  AC.  IK/L  I KA  -AVWv—r—x +5V,D.C: M600  pl|i2|N(io1[9lfe  22  K A  @  2N4I26  f-^WW77?T7T  F i g u r e 52.  C i r c u i t diagram o f t h e b o u n c e l e s s s w i t c h and power s u p p l y used i n t h e air-mercury experiments.  3^  APPENDIX I I CONTOUR PROGRAM  F o l l o w i n g i s an example o f t h e computer program used t o produce t h e c o n t o u r maps o f gas volume f r a c t i o n and bubble f r e q u e n c y .  CNT0UR i s a  sub-program a v a i l a b l e i n t h e UBC computing c e n t r e l i b r a r y w h i c h a l l o w s an i r r e g u l a r g r i d o f v a l u e p o i n t s to, be r e p r e s e n t e d as a c o n t o u r map.  two-dimensional  c  PRCCRAC TC CCNTCUF XY PLANES FCC FUN FG 2 DIMENSICN X P l l l ) , 1 F U 5 ) , Z F I U . 1 9 ) , TITLEI20) CALL FLCTS SET LP >F £ YF ARRAYS c 0L03"" R E A D l 5 , I O C ) MOFDAT 99 FCFNATU1) . CCC4 100 IF(yCRCAT.EC.l) GC TC 3C4 0C05 READI5.2C5) ( T I T L E ( I ) 1 - 1 , 2 C ) 0006 FCFMA7(20A4) 305 CCC7 GC08 XPI1) = C . £ CC 101 1=2, 11 0109 XP(I)=>F(1-11+1.0 CC10 CONTINLE 101 0011 Y P ( 1 ) = 1.3 0012 DC 1C2 1=2,8 CC13 YP( I ) = YPI I-11 + C . 5 0014 CCNTINLE 102 0015 YP(5)=YF(8)+0.2 0016 YP( 10 ) = YP( 9 ) f C . 2 0017 CC 1C3 1 = 1 1 , 1 9 0G18 Y P(I>=YF(I-11+C.5 0C19 CONTINUE 103 C020 F L C T . T h e AXES C C A L L A X I S I C . C C . C M - C R I Z C N K L C I S T A N C E PARALLEL TC N C Z Z L E IN C M . ' , 0021. 1 - 4 5 , 1 2 . 0 , 0 . 6 , - 5 . 0 , 1.0) C A L L A X I S I C . O . C . O , ' F C R I Z C N T A L C I S T A N C E PERPENDICULAR TO NOZZLE IM 0022 1CM. • , + 49 , 1 C . C, .C. C , - 5 . 0 , 1 . C I CALL SYKECL (0 .5 , 9 .5 ,0 . 1 4 ,T ITL E , C . , EO ) 0023 READ IN Th 2 DATA c DC 2C1 1 = 1 , 1 1 0024 FEiC(5,2) < Z F ( I , J ) , J=l, 1 9 ) C025 FQRNAT<4X,19F4.C> 0026 2 CCNT I M F 201 0027 FLCT THE C C M C U R S ' C DC 2C2 1 = 1 , 1 1 0028 I F I I . E C . 1 1 1 G 0 TO 2 C 1 0029 CN=FLCAT(I)*10.0 0C30 GO TO 2C2 0031 CCNTINUE 301 0032 CN=1.C 0033 CONTINLE 0024 202 CALL CNTCUF(XP,11,YP,19,ZP,11,CN,3.0,CN) 0035 CCNTINLE CC36 303_ CALL P L C T l 1 4 . C 0 . C ,-2) 0037 GC TC 99 CC36 CCNTINLE 0C39 204 C A L L FLCTND 0040 0041 STCP EN'D 0042 * C P T IONS IN" E F F E C T * IC, E6CC IC , SCUR CE ,.NOL I S T , NGOECK ,LCAD .NCMAP * O P T I C N S IN E F F F C T * NAPE = .*AIN , LINECNT = 57 _ _ _ _ » S T A T I SJ I C_Sj?__ SOURCE STA T_EME N TS _=_ _. 4 2 , F F C G PAf SI 2 E_j= 254 6 • STATISTICS* N'C C IAGNC ST ICS G~EN E~RAT tO NC ERRORS IM f-'AIN 0001 0002  .  1  J  C  NC STATEMENTS FL A G G E C E X E C L T I CN T E R M NATEC  IN  T t- E A B C V E CCMt> IL AT I CN 5  1. 003 2.000 3.000 4. 000 5.000 6. COO 7. COO 8.000 9. OOO 1C.000 .11.000 12.003 13.000 14.000 15.00C 16.000 17.000 18.000 19.000 2C. COO 21.000 22.000 2 3 . COO 24.000 25.000 26.000 27.000 28.000 2 9 . 000 3C.000 3 1 . 000 ' 22.0CO 33.000 3 4 . 000 25.0CC 36.000 37.COO 38.000 39.000 4 C . 000 41.000 42.000 43.CCO 44.000 4 5 . 000 46.CCO 47.000 4 8 . COO 49.000  APPENDIX I I I .  GAS DISTRIBUTION CONTOUR MAPS.  A complete s e t o f c o n t o u r maps d e p i c t i n g the v o l u m e t r i c gas d i s t r i b u t i o n w i t h i n t h e j e t o f r u n HG 1 i s i n c l u d e d i n t h i s appendix. contoured  Each  plane i s l a b e l l e d according t o t h e  nomenclature d e s c r i b e d i n F i g u r e 18.  X=-2.0 o  CD  pj o z  z:  o  d o UJ  o CL  I—  ~= ceo  . UJ_;-  Sim  O Z  O  o z cr t—  GC  : CCo  , UJ_;  o  -4.0  -3.0  —I -2 0  1 -1.0  i 0.0 HORIZONTAL  'Jo. JO!  sniv./ii.  "I— 1.0 DISTANCE  "I 2.0 P A R A L L E L  1  3.0 TO  NOZZLE  T 5.0  1 4.0 IN  CM.  6.0  7.0  8.0  N o . -:C!  10 O I V . / l N .  x=-o.2:  UJ  _lo  o z  o UJ  o z cc I—  Qra" (X  o ceo  UJ_;-  -4.0  -3.0  —I  -2.0  ,  :  1.0  T  0.0  HORIZONTAL  1 i.O DISTANCE  r— 2.0 P A R A L L E L  1 3.0 TO  I  1 4.0  1  NOZZLE  No  IN  ai'.l  5.0  C M .  ISDiV/lU.  6..0  ~I  7.0  S.O  CD  : x=-o.i  j  _ i v  _  i  1—:  Run  n  1  HG I  1  Volume  -4-  %  Air  N' d  -4.0  -3.0  1 -2.0  0  .1 '  T 0.0 HORIZONTAL  T 1.0 DISTANCE  1 2.0 P A R A L L E L  1 3.0 TO  NOZZLE  1  1 5.0  4.0  IN  CM.  0  Fr  =105 = 0.325 cm  1 6.0  r—  7.0  a.o  X=0-.2  h-  1  N<>.  40i  in  i)iv  AN.  X=l .0  Sim"  UJ  o  o CCc:  UJ o  •—.a  Onl"  cr CCO  uJ_;-  -4.0  -3.0  ~t  -2.0  1  -J.0  1  1  1  1  1  0.0  1.0  2.0  3.0  4.0  HORIZONTAL  DISTANCE  P A R A L L E L  TO  NOZZLE  IN  —1— e.o  r—  5.0  7.0  CM.  Mo  .-.01  USIVC/IM.  —1 : e.o  SfrT  !. X=2.0  ;o Di v  AM  :  i  Z=-0.7J  '  rvi" rvi o  QlCC  _)  CJ Q  cc UJ  »— CO  a  j o <XfM. r— I z o rvi  "iTi'-'i 'IT'!":  •—»  a: Oo  -4.0  i  -3.0  i  -2.0  :  i  -1.0  i  0.0 HORIZONTAL  1 t.O DISTANCE  \ 2.0 P A R A L L E L  1 3.0 TO  NOZZLE  1 4.0 IN  1— 5.0 CM.  e.o  7.0  8.0  Z---0.2  CO  CH-.WT  01  frST  ^ /(.V..  i Z = 0 . 3  .- 1 ,  CJ  UJo  (VI O  ST _J o a  £ cr  c  UJ  a. i r— CO  -J°. C X f M .  o •rvi•—• O o X.  1  -i -4.0  -3.0  -2.0  _i  n  nn HORIZONTAL  1  :  10 D I S T A N C E  1  :  2.0 P A R A L L E L  1  1  3.0  4.0  TO  N O Z Z L E  ' IN  5.0 C M . c n A [ 7 r NO. o:  i —  5.0  r  -  7.0  i  8.0  .1  AST  CHART  NO  CI  o  091  T9T  Z9T  6 o  e9T  z  *9T  S9I  991  Z.9T  89 [  169  CUT  " r=e.s  :  TZ  LJr>  O  T.  cn — cn _i  ZD  r  <_>  o za  (  or 0_  I  •  : I  :— I iV> i *—»  a  '•|:  !_ja . CCoi  t—  . zr O rvj  . . -"-an i  —I -2.0.  -1.0  0.0  •  i n V E R T I C A L  1 2.0  '—l 3 0  DISTANCE  FROM  1 4.0 NOZZLE  1 5.0 IN C M .  1 6.0  - i — 7.0  —1 8.0  APPENDIX IV BUBBLE FREQUENCY DISTRIBUTION CONTOUR MAPS  A complete s e t o f c o n t o u r maps d e p i c t i n g t h e bubble f r e q u e n c y d i s t r i b u t i o n w i t h i n t h e j e t o f r u n HG 1 i s i n c l u d e d i n t h i s appendix.  Each c o n t o u r e d  p l a n e i s l a b e l l e d a c c o r d i n g t o t h e nomenclature d e s c r i b e d i n F i g u r e 18.  X=-3.5  N'T  :('•!  !C-tiiV./;N  o 0~  X=--3.0  .o CJ  rvi  o UJ  cr i— •  cr CJ  CCO UJ _•-  -4.0  -3.0  -2.0  -1.0  0.0 HORIZONTAL  1 DISTANCE  1 P A R A L L E L  .—!  -1—  , —  3.0 TO  NOZZLE  4.0 IN  CM.  5.0  I—  6.0  —1— 7.0  -1 8.0  X=-2.5  O  o UJ  (X  cn  ocr i CCO  ; CiJJ-  tn _|  -4 0  P  -3 0  j  -2.0  ,  -1.0  ,  1 0.0  HORIZONTAL  1 1.0 DISTANCE  1 2.0 PARALLEL  1  1  3.0 TO  1  4.0 NOZZLE  IN  5.0 CM.  1— 6.0  7.0  S.O  N o . /101  »0PIV./lN  HORIZONTAL  DISTANCE  P A R A L L E L  TO  NOZZLE  IN  CM.  No  *'»  l';Di'.'/iN  X=r0.5;  "M—— -4.0  ;  1  -3.0  1  -2.0  •  1  -1.0  T  0.0  1  1.0  :  r  2.0  —i  3.0  1  4.0  '  HORIZONTAL DISTANCE PARALLEL TO NOZZLE IN CM.  1 — —  5.0  1  6.0  1  7.0  1 8.0  -I  ?H  -4.0  ;  , 1 -3.0  .... 1  •.,! 1 -2.0  .....i 1 -1.0  .  .... 1 0.0  : 1 1.0  . :  1 2.0  1 3.0  , 1 4.0  HORIZONTAL DISTANCE PARALLEL TO NOZZLE IN CM. M o . 401  10DIV./IN  I • 1 5.0  ;  i 1 6.0  I  ; • r—  7.0  1 8.0-  No.  ACl  iO Dt V. / i N .  f„v> /.(•;  ;0O;V/iN.  X=2.0  .o  xiid"  O  UJ  cr Qi>i"  cr o  00  4.0  -3.0  -2.0  1  1.0  1 0.0  1 1.0  I  2.0  1 3.0  T 4.0  HORIZONTAL DISTANCE PARALLEL TO NOZZLE IN CM.  5.0  -1— 6.0  -1 7.0  8.0  No. -ill  10 D I V / l N  OiV/iN  <_>  UJo rvi' o  ce-  cz _i  r> t_)  az = »  uJ  _  a.  c  cc UJ o_  CJ Z->C  a _i=  CEfM. r— 1  z o rvi •  cc  1—  1  -4.0  -3.0  -2.0  1 1  :  1  2  q  T 3.0  T 4.0  ' H0RIZ0NTflL DISTANCE PARALLEL TO NOZZLE IN CH. 0  5.0  ~I— 6.0  —I  1.0  B.O  193  Bubbles  Rum HG I  Per Second  N'p, =105 'Fr  d  UJo rvi O  cc(X —1  '  3 CJ  az ° :£= UJ  o_ cf •  — I ; <^  a CEoi : »—i  ' cc :  No.  DIV / I N .  0  = 0.325 cm  6.0  10 L)l V/itsl.  861  Z=6.3  '2.5  T:  c_> : UJo  rvi O  cr CJ  oz =  w°  r—  -LLtLliilii;  cio :  t—t  ;0  l-J . i 0  z  rvi  rr  • i  .i  O o  I  to o o i -5.0  NO.  Ol  -!.0  1  1  1  0.0  1.0  2.0  •  1 3.0  1—: 4.0  r — ' 5.0  VERTICAL DISTANCE FROM NOZZLE IN CM.  1— 6.0  -|—  7.0  S.G  TO?!  zoz  £0Z  204  SOZ  r H O R I Z O N T A L  -5 0 I  i 90Z  -4.0 I  -3.0 I  -2.0 I  DISTANCE PERPENDICULRR  -1.0 I  0.0 J-  TO NOZZLE IN Crl'  !.0 1  2.0 1  :  3.0  1  •  4.0 -1 >  j  5.  1  LOZ  to O CO  2.0  -3.0  T 0.0  "I  T 2.0  1 3.0  1 4.0  r 5.0  VERTICai DISTANCE FROM NOZZLE IN CM.  r o.o  T 7.0  8.0  60Z  210 REFERENCES (1)  T h e m e l i s , N.J., McKerrow, G.C., T a r a s s o f f , P. and H a l l e t t , G.D., J . M e t a l s , V o l . 24. No. 4, 1972, pp. 25-32.  (2)  B a i l e y , J.B.W., Beck, R.R., H a l l e t t , G.D., Washburn, C. and Weddick, A . J . "Oxygen S m e l t i n g i n t h e Noranda P r o c e s s " , Paper P r e s e n t e d a t t h e 104th AIME annual m e e t i n g , New York C i t y , N.Y., F e b r u a r y 16-20, 1975.  (3)  B r a n t l e y , F.E. and Schack, C.H., Rep. I n v e s t . 6113, 12 pp.  (4)  O u d i z , J . 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