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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 the Department of METALLURGY We accept t h i s t h e s i s as conforming t o standard required from candidate f o r t degree of MASTER OF APPLIED SCIENCE THE UNIVERSITY OF BRITISH COLUMBIA J u l y , 1975. In presenting th i s thes i s in pa r t i a l fu l f i lment o f the requirements fo r an advanced degree at the Univers i ty of B r i t i s h Columbia, I agree that the L ibrary sha l l make it f ree ly ava i l ab le for reference and study. I fur ther agree that permission for extensive copying of th i s thesis for scho lar ly purposes may be granted by the Head of my Department or by his representat ives . It is understood that copying or pub l i ca t ion of th is thesis fo r f i nanc ia l gain sha l l not be allowed without my writ ten pe rm i ss ion . Department of ftlBfft it U jl& The Univers i ty of B r i t i s h Columbia 2075 Wesbrook Place Vancouver, Canada V6T 1W5 i i 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 of 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 of mercury were s t u d i e d under i s o t h e r m a l , non-reactive c o n d i t i o n s f o r n o z z l e diameters of 0.325 cm. and 0.476 cm. and over a range of modified Froude numbers w i t h values from 20 to 300. A s p e c i a l l y -designed e l e c t r o - r e s i s t i v i t y probe allowed the measurement of gas volume f r a c t i o n and bubble frequency at 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 of these values has been expressed as a s e r i e s of contour maps on a grid-sequence of orthogonal planes. J e t cone angle, diameter, and pene-t r a t i o n distances were measured and compared to values ob-tained under s i m i l a r c o n d i t i o n s i n the ai r - w a t e r system. The events o c c u r r i n g i n the development of a submerged gas j e t i n a l i q u i d were stud i e d by means of h i g h -speed cinematic photography i n the a i r - w a t e r system. Mathematical models p r e d i c t i n g j e t behaviour have been examined i n the air-mercury system and the e x t r a p o l a t i o n of experimental r e s u l t s to i n d u s t r i a l copper c o n v e r t i n g and steelmaking operations has been discussed. i i i TABLE OF CONTENTS Page ABSTRACT i i TABLE OF CONTENTS • i i i LIST OF FIGURES v i i LIST OF TABLES 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 Industry 1 1.1.2 The Iron and S t e e l Industry . . 3 1.1.3 Other Metal I n d u s t r i e s . . . . 5 1.2 Tec h n i c a l Background and Previous Studies 7 1.2.1 The Formation of Gas Bubbles i n a l i q u i d 7 1.2.2 Shape and Rise V e l o c i t y of bubbles 11 1.2.3 Homogeneous J e t s 14 1.2.3.1 Behaviour of Homo-geneous j e t s 14 1.2.3.2 J e t Cone Angle . . . . 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 t r a j e c t o r y 21 1.2.4 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 Previous 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 Apparatus 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 3.1.2 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 of Mercury Backflow i n t o the tuyere . . . . 3.1.6 E v a l u a t i o n of Equipment performance . 3.1.7 S t a t i s t i c a l E v a l u a t i o n . o f data r e p r o d u c e a b i l i t y .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 Apparatus 3.2.2 Elapsed-time photography 3.2.3 J e t Determination 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 cinematic photography . . 3.2.5 Slug flow measurements V Page 4. RESULTS , 6 3 4.1 Submerged H o r i z o n t a l A i r J e t s i n Mercury 63 4.1.1 Volumetric 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 frequency d i s t r i b u t i o n . . . 71 4.1.3 V e l o c i t y measurements 86 4.1.4 Measurements of mercury backflow 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 87 4.2.1 Elapsed-time photography 88 4.2.2 T r a j e c t o r y determination by probe and photography 90 4.2.3 Observations of J e t p u l s a t i o n . . . 91 4.2.4 Observations of slugging behaviour. 96 5. DISCUSSION 99 5.1 General 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 . 99 5.2 Cone Angle 100 5.3 J e t Diameter 107 5.4 J e t T r a j e c t o r y 109 5.5 J e t P e n e t r a t i o n 114 5.6 O r i g i n s of J e t Behaviour 119 5.6.1 J e t P u l s a t i o n s 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 v l Page S.7 Extension to i n d u s t r i a l systems 121 5.7.1 Physical properties of the l i q u i d . 121 5.7.2 Phenomenological comparison . . . . 123 5.7.2.1 Tuyere plugging i n the l a d l e desulphurization of s t e e l . . . . . . . . . . . 123 5.7.2.2 Tuyere erosion during copper converting . . . . . 125 5.7.2.3 Back-wall erosion i n a copper converter . . . . . 126 6. CONCLUSION. . . . . . . . . . . . . . . . ... • • 127 6.1 Summary 127 6.2 Suggested Future Work 128 APPENDIX I 130 APPENDIX I I . 133 APPENDIX III 135 APPENDIX IV 172 REFERENCES 210 L i s t of Figures Page Figure 1. V a r i a t i o n of mean bubble diameter w i t h o r i f i c e diameter and Reynolds number f o r the air - w a t e r system. From Leibson et a l (37). Figure 2. Schematic diagrams of j e t flow 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 at 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 Szekely and Themelis (85). Figure 3. J e t v e l o c i t y p r o f i l e s i n r a d i a l s e c t i o n s at d i f f e r e n t distances (x) from o r i f i c e . From Szekely and Themelis (85). Figure 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) . Figure 5. Schematic of apparatus employed i n the study of air-mercury j e t s . Schematic of mercury tank. Photographs of the converter-type tank and a n c i l l a r y apparatus used i n the air-mercury t e s t s . Schematic of e l e c t r o r e s i s t i v i t y probe. Schematic of e l e c t r o n i c apparatus employed i n the study of air-mercury j e t s . S e c t i o n a l diagram of t e f l o n nozzle used i n the determination of mercury backflow. A Voltage pulse recorded at a t r a c e speed of 2 ms. / d i v i s i o n , or 500 cm./s. F i v e f a s t voltage pulses viewed at a t r a c e speed of 1 ms. / d i v i s i o n , or 1000 cm/s. Os c i l l o s c o p e t r a c e s showing voltage pulses caused by bubbles passing the p r o b e - t i p , with corresponding c o u n t e r - b l i p s above. 10 Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure Figure 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 15a 15 17 18 34 37 38 40 42 47 49 50 52 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 . 5^ Photograph of a "catch-box" used i n the measurement of s l u g flow. 6 0 I l l u s t r a t i o n of catch-box placement i n the measurement of the slug - f l o w . 61 v i l i Page Figure 16. Probe t r a c e through an air-mercury 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 Figure 17. Probe t r a c e through an air-mercury j e t showing bubble frequency p r o f i l e . 65 Figure 18. I l l u s t r a t i o n of g r i d - p l a n e placement and nomen-c l a t u r e as used i n contour mapping. 68 Figure 19. Contour map of volume percent a i r f o r the plane 2 = 1.3 of run HG1. 69 Figure 20. Contour map of volume percent a i r f o r the plane X = 0 of run HG1. 70 Figure 21. Contour map of volume percent a i r f o r the plane & = 1.3 of run HG2. 7 2 Figure 22. Contour map of volume percent a i r f o r the plane X = 0 of run HG2. 7 3 Figure 23. Contour map of volume percent a i r f o r the plane 2 = 1.3 of run HG 3. 74 Figure 24. Contour map of volume percent a i r f o r the plane X = 0 of run HG 3. 7 5 Figure 25. Contour map of volume percent a i r f o r the plane S = 1.3 of run HG 4 . 76 Figure 26. Contour map of volume percent a i r f o r the plane X = 0 of run HG 4. 77 Figure 27. Contour map of bubble frequency f o r the plane a = 1.3 of run HG 1. 78 Figure 28. Contour map of bubble frequency f o r the plane X = 0 of run HG 1. 7 9 Figure 29. Contour map of bubble frequency f o r the plane a = 1.3 of run HG 2. 80 Figure 30. Contour map of bubble frequency f o r the plane X = 0 of run HG 2. 81 Figure 31. Contour map of bubble frequency f o r the plane 3 = 1.3 of run HG 3. 82 Figure 32. Contour map of bubble frequency f o r the plane X = 0 of run HG3. 8 3 ix Page Figure 33. Figure 34. Figure 35. Figure 36. Figure 37. Figure 38. Figure 39. Figure 40. Figure 41. Figure 42. Figure 43. Figure 44. Figure 45, Figure 46. Figure 47, Figure 48, Contour map of bubble frequency f o r the plane 2 = 1.3 of run HG4. Contour map of bubble frequency f o r the plane X = 0 of run HG 4. Elapsed-time photograph of a submerged a i r j e t i n water. Two p i c t u r e s of the 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 to show the 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 . Probe t r a c e through an a i r - w a t e r j e t . The envelope and t r a j e c t o r y of an air-wat e r j e t as determined by photography and probe. N' = 1500. Fr The envelope and t r a j e c t o r y of an ai r - w a t e r j e t as determined by photography and probe. N' p r = 6700. A sequence of frames showing one complete p u l s a t i o n of an a i r j e t i n water. A sequence of frames showing the development of a s l u g . 84 85 89 92 93 94 95 97 I l l u s t r a t i o n of the flow p a t t e r n i n the catch box. 98 Time-lapse photograph of an air-wat 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 during the air-mercury t e s t s . The cone angle i s 20°. 103 J e t width vs. tuyere submergence. Traverse taken at 0.3 cm. above the tuyere f o r Run HG4. 105 Je t width vs. tuyere submergence. Traverse taken at 1.3 cm. above the tuyere f o r Run HG 4. J e t diameter vs. dis t a n c e along t r a j e c t o r y . 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 1. 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 2. 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 3. 106 108 110 111 112 X Page Figure 49. Figure 50. Figure 51. Figure 52. 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. Photo i l l u s t r a t i n g lance plugging due t o back-flow of l i q u i d s t e e l i n t o a lance. Courtesy of Wood, et a l (86). C i r c u i t diagram of the i n t e g r a t o r used i n the air-mercury experiments to measure gas volume f r a c t i o n . 113 124 131 C i r c u i t diagram of the bounceless switch and power supply used i n the air-mercury experiments. 132 x i 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 of 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 air-mercury system. 66 TABLE I I I . J e t cone angles measured at a h o r i z o n t a l d i s t a n c e of 0.5 cm. from the noz z l e . 102 TABLE IV. Experimental j e t p e n e t r a t i o n d i s t a n c e s at a v e r t i c a l d i s t a n c e above the noz z l e of 6.3 cm. 115 TABLE V. Comparison of experimental and t h e o r e t i c a l j e t p e n e t r a t i o n d i s t a n c e s at a v e r t i c a l d i s t a n c e above the nozzle of 6.3 cm. 117 TABLE VI. Comparative p h y s i c a l p r o p e r t i e s of a i r , water, mercury, l i q u i d copper, and l i q u i d i r o n or s t e e l . 122 Acknowledgement I would l i k e to 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 guidance throughout the course of t h i s research p r o j e c t . I would a l s o l i k e t o thank E. Klassen and D. Brandys f o r t h e i r c o n t i n u a l work i n the design and c o n s t r u c t i o n of the e l e c t r o n i c apparatus 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 expressed to the Noranda Group who s u p p l i e d f i n a n c i a l support during t h i s e n t i r e research p r o j e c t through a Noranda Graduate Research Fell o w s h i p . 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 Processes The a r t of blowing submerged gas j e t s i n t o l i q u i d metals i n order to ob t a i n high 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 to many important m e t a l l u r g i c a l processes. Copper matte converting i s w e l l e s t a b l i s h e d 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 the obvious example of t h i s a p p l i c a t i o n . However, the l i s t of such processes i s l a r g e and, i n recent years, has been growing q u i c k l y to i n c l u d e the gaseous deoxidation of copper, the new continuous copper smelting process developed by Noranda, many v a r i a t i o n s on bottom-blown steelmaking processes, as w e l l as l a d l e degassing and d e s u l p h u r i z a t i o n . Several of the more prominent process a p p l i c a t i o n s w i l l now be discussed i n terms of t h e i r u t i l i z a t i o n of submerged gas j e t s . 1.1.1 The Copper Industry The p y r o m e t a l l u r g i c a l production of copper commonly in v o l v e s the process of "converting", which t r e a t s the matte r e s u l t i n g from previous smelting operations to produce a product known as b l i s t e r copper, c o n t a i n i n g 2 about 99% copper and small amounts of base metal i m p u r i t i e s . Since the t u r n of the century, t h i s process has almost u n i v e r s a l l y been conducted i n a Peirce-Smith converter, 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 long by 13 f e e t i n diameter. A bank of h o r i z o n t a l tuyeres i s l o c a t e d along the le n g t h of the converter below the l e v e l of the l i q u i d s u r f a c e . The i r o n and sulphur are o x i d i z e d by blowing a i r through the molten matte; sulphur i s removed i n the gases as SC^ while the i r o n i s o x i d i z e d and slagged o f f . In March, 197 3, the Noranda Process Continuous Smelter (1,2) began f u l l - s c a l e o p eration t o smelt 800 tons a day of sulphide copper concentrate d i r e c t l y to m e t a l l i c copper, combining both the smelting and con-v 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 continuous, dynamic e q u i l i b r i u m . E f f i c i e n t heat and mass t r a n s f e r are obtained by blowing a i r , or oxygen-enriched a i r , through a s e r i e s of submerged h o r i z o n t a l tuyeres, thus maintaining a p o r t i o n of the r e a c t o r bath i n a h i g h l y -t u r b u l e n t s t a t e . The b l i s t e r copper produced i n a copper converter or by the Noranda Process i s s t i l l u s u a l l y too impure f o r d i r e c t use and must be r e f i n e d to produce commercial grades of copper. This r e f i n i n g procedure again i n v o l v e s 3 the use of submerged gas j e t s . I m p u r i t i e s such as Fe, Sn, Sb, Zn and some of the N i , Co, and Pb i n the molten b l i s t e r copper are o x i d i z e d i n an anode furnace by means of submerged i n j e c t i o n of a i r or oxygen-enriched a i r . The impurity-metal oxides are e i t h e r v o l a t i l i z e d or skimmed o f f as a s l a g . The r e s u l t i n g oxygen-rich copper i s then t r e a t e d by an operation known as p o l i n g , i n which wooden poles are t h r u s t i n t o the bath and burn t o evolve reducing gases which react w i t h the oxygen i n the copper. C u r r e n t l y , the p o l i n g procedure i s being replaced i n many p l a n t s by the d i r e c t submerged i n j e c t i o n of v a r i o u s reducing gases (3,4). The reducing gas, which i s i n t r o -duced through the e x i s t i n g nozzles f o l l o w i n g the 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), or 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 (11). 1.1.2 The Iron and S t e e l Industry Submerged gas i n j e c t i o n was f i r s t used commercially i n the production of s t e e l as e a r l y as 1860 when the Bessemer bottom-blown a c i d process f o r c o n v e r t i n g b l a s t -furnace 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 process 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 blowing a c o l d a i r j e t v e r t i c a l l y upwards through the molten metal bath. In 1879 the Thomas process, i n v o l v i n g the same blowing c h a r a c t e r i s t i c s as 4 the Bessemer process, was patented 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 of the use of a b a s i c l i n i n g and f l u x which allowed the smelting of high-phosphorous ores common t o many regions of Europe. Both the Thomas and Bessemer processes, however, were soon replaced by open-hearth steelmaking and the BOF, whereupon the use of submerged gas j e t s i n the r e f i n i n g of s t e e l was l a r g e l y ignored u n t i l more recent times. Bottom-blown steelmaking, 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 the develop-ment of a c o n c e n t r i c tuyere which allows 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 times, to be s h i e l d e d w i t h another gas, thus e l i m i n a t i n g extremely high temperatures adjacent to the bottom r e f r a c t o r i e s . The OBM or Q-BOP process (15) i n j e c t s oxygen s h i e l d e d w i t h propane or any other hydrocarbon gas, whereas the LWS process s h i e l d s the oxygen w i t h steam or f u e l o i l . Both the OBM and LWS ve s s e l s are s i m i l a r i n c o n f i g u r a t i o n and operation to a Bessemer converter. The Submerged I n j e c t i o n Process (SIP) i n j e c t s the gas n e a r - h o r i z o n t a l l y i n t o an open-hearth furnace to a c c e l e r a t e normal open-hearth r e f i n i n g r a t e s . 5 In a d d i t i o n , two new processes f o r s t a i n l e s s s t e e l production, the AOD (16, 17) and CLU (18) processes, are both based on the submerged i n j e c t i o n of gases i n t o a l i q u i d metal bath, and argon ladle-degassing (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 to 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 Metal I n d u s t r i e s Recently many companies have been l o o k i n g i n t o the d i r e c t smelting of lead concentrates and s e v e r a l of the r e s u l t i n g processes are based on submerged gas i n j e c t i o n (21,22). The St. Joe Minerals Corp. has developed a Peirce-Smith type converter f o r the submerged smelting of lead concentrate (23) . The Queneau-Schuhmann process (24) provides continuous autogenous conversion of sulphide ore concentrates i n a s i n g l e v e s s e l by means of submerged oxygen blowing, and claims a p p l i c a b i l i t y to the treatment of many metal sulphides such as copper, n i c k e l , c o b a l t and lead. Noranda has a l s o patented a process f o r c o n t i n -uous lead smelting which i s s i m i l a r to t h e i r Noranda Process f o r copper, mentioned e a r l i e r . In a d d i t i o n , the submerged smelting of t i n s l a g s i s c u r r e n t l y being examined (25) w i t h a view t o the 6 p o s s i b i l i t y of t r e a t i n g lower-grade concentrates. I f one considers as w e l l the many operations 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 only the momentum of the 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 of o p p o r t u n i t i e s to enhance the t r a n s f e r of heat, mass and momentum i n many m e t a l l u r g i c a l operations. 7 1-2 Tec h n i c a l Background and Previous Studies 1.2.1 The Formation of Gas Bubbles i n a L i q u i d There i s general agreement among i n v e s t i g a t o r s (26-53) t h a t three d i s t i n c t regimes of bubble formation may be i n d e n t i f i e d as a f u n c t i o n of gas f l o w r a t e . (i) The s t a t i c regime: At very low gas flow r a t e s , of the order of 1 ml/s. (N R e.< 500), the frequency of bubble formation i s p r o p o r t i o n a l to the gas fl o w r a t e and the bubble s i z e i s almost constant. The bubble frequency i s u s u a l l y below 100 bubbles per minute. At these v a n i s h i n g l y small gas flows the formation of a bubble may be described i n 4 3 terms of a balance between a buoyancy f o r c e , n R B ( p L - P ( _ . ) g, and a surface tension f o r c e , 2 I T r 0 a(cos -6H f ( % , whe r e : R_, = r a d i u s of the bubble at the moment of r e l e a s e hi p = d e n s i t y of the l i q u i d L P G = d e n s i t y of the gas g = g r a v i t a t i o n a l a c c e l e r a t i o n r G = rad i u s of the o r i f i c e o = surface t e n s i o n of the l i q u i d •0- = angle of contact at the t r i p l e i n t e r f a c e f (—°-) = a shape f a c t o r which, f o r a sphere, has the value 1. I f i t i s assumed t h a t there i s p e r f e c t w e t t i n g of the o r i f i c e by the l i q u i d then <3- =F 0 and equating the two 8 f o r c e s y i e l d s the bubble s i z e : ' fc-V]V3<1-1) The bubble diameter 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 the cube ro o t of the o r i f i c e diameter but i s independent of the gas f l o w r a t e . ( i i ) The dynamic regime: Up t o a gas f l o w of about 100 mL£. (500 < N_. < 2100), i n v o l v i n g bubble x\.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 than 500 bubbles per minute, the bubble volume in 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 the frequency of formation remains almost constant. Davidson (35) and Amick e m p i r i c a l l y d e r i v e d the f o l l o w i n g equation f o r the maximum bubble frequency i n the a i r - w a t e r system: f =12.3 Q 0- 1 3 d o " 0 , 4 3 (1.2) max where f = maximum frequency of bubble formation max 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 diameter ( i i i ) Non-homogeneous j e t : At very h i g h gas f l o w -r a t e s (2100<N ) the bubble stream can best be d e s c r i b e d as a j e t . The l a r g e r bubbles or a i r - s t r e a m i s s u i n g from the o r i f i c e v i r t u a l l y explode i n t o s m a l l bubbles very c l o s e to the o r i f i c e . Leibson et a l (37) have measured the v a r i a t i o n of bubble s i z e w i t h Reynold's number over a l l the bubbling 9 regimes. Their c o r r e l a t i o n f o r the ai r - w a t e r system i s presented g r a p h i c a l l y as Figure 1. I t can be seen t h a t the bubble s i z e decreases 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 th a t f o r 10,000< K e . N„ the mean bubble diameter i s almost constant at 0.5 Re. cm. 10 Figure 1. V a r i a t i o n of mean bubble diameter w i t h o r i f i c e diameter and Reynolds number f o r the ai r - w a t e r system. From Leibson et a l ( 3 7 ) . 11 1.2.2. Shape and Rise V e l o c i t y of Bubbles In a d d i t i o n t o the work on bubble 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 concerned w i t h the shape and r i s e behaviour of e i t h e r s i n g l e bubbles or bubble chains (27, 30, 32 and 55-59) or of bubble swarms (36,56, 60). As was the case w i t h the t o p i c of bubble formation, i t i s convenient 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 of bubbles t o speak of regions of behaviour, i n t h i s case of r e g i o n s d e f i n e d by a range of bubble Reynold's number ( ) • b (i ) Very small bubbles (N D^ ^ 2 ) r i s e at a t e r m i n a l v e l o c i t y d e f i n e d by Stokes 1 law: R e b UT = -4^- g ( p L _ p G ) (1.3) where u = t e r m i n a l r i s e v e l o c i t y of the bubble d, = bubble diameter b y L = v i s c o s i t y of the l i q u i d . The bubblesmay be considered to behave as r i g i d spheres, ( i i ) Larger s p h e r i c a l bubbles (2 <j N_ < 400) r i s e K e b at a v e l o c i t y which i s up t o 50% g r e a t e r than t h a t p r e d i c t e d by Stokes' law. This behaviour has been a t t r i b u t e d to 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 consequently reduces the drag f o r c e . 12 ( i i i ) Bubbles i n the range 400 < <5000 tend K e b to f o l l o w a h e l i c a l or zig-zag path and are 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) Bubbles l a r g e r than 1 cm i n eq u i v a l e n t diameter (5000 <N R S J 3 ) assume a s p h e r i c a l - c a p shape. Although they tend to o s c i l l a t e s l i g h t l y as they r i s e , they appear to r i s e at a uniform v e l o c i t y which i s i n -dependent of 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 . Davies and Taylor (55) deriv e d the f o l l o w i n g equation f o r the t e r m i n a l v e l o c i t y of a sp h e r i c a l - c a p bubble: u,p = 1.02 { - ^ - ) h (1.4) where d^ = equivalent diameter (diameter of a sphere of equivalent volume) In a d d i t i o n , therehave been i n v e s t i g a t i o n s concerning the r i s e behaviour of bubbles as a f u n c t i o n of 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 . Datta et a l (30) and Abdel-A a l e t a l (59) agree that bubble volume increases w i t h l i q u i d surface t e n s i o n ; but whereas Datta f i n d s very l i t t l e v i s c o s i t y e f f e c t , Abdel-Aal f i n d s l a r g e r bubbles i n l i q u i d s of lower v i s c o s i t i e s . Siemes and Gunther (36), when viewing bubble swarms, a l s o found t h a t i n c r e a s i n g the surface t e n s i o n increases the bubble volume (they measured a decrease i n s p e c i f i c surface area) and det e r -mined that i n c r e a s i n g the v i s c o s i t y (to above 20cp) pro-duces mostly la r g e bubbles w i t h i n a narrow s i z e range because the viscous l i q u i d does not permit strong turbulence above the nozzle (which would normally cause bubble break-up). 14 1.2.3 Homogenous J e t s 1.2.3.1 Behaviour of Homogeneous J e t s When a f l u i d of uniform i n i t i a l v e l o c i t y ( u 0 = const.) i s discharged 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 surface i s created between the moving f l u i d , or j e t , and the ambient medium (Figure 2). Parameters such as flow v e l o c i t y , temperature, and specie 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 i n h e r e n t l y unstable, causing eddies to move i n a d i s o r d e r l y f a s h i o n both along and across the stream, which i n t u r n e f f e c t a transverse t r a n s f e r of momentum, heat, and c o n s t i t u e n t s or mass. There i s , then, a boundary l a y e r across which these parameters vary continuously between t h e i r i n i t i a l values i n the dis c h a r g i n g f l u i d and t h e i r values i n the ambient medium. The j e t expands by e n t r a i n i n g f l u i d from the surrounding medium. Consequent to t h i s entrainment the parameters of v e l o c i t y , temperature and con c e n t r a t i o n become more d i f f u s e and the core of f l u i d w i t h i n which the parameters remain at i n i t i a l values g r a d u a l l y d i m i n i s h e s . The length of the j e t over which t h i s " p o t e n t i a l core" e x i s t s i s termed the i n i t i a l flow r e g i o n i n Figure 2, and t y p i c a l l y has a length of between four and s i x nozzle diameters. A short d i s t a n c e downstream from the i n i t i a l 15 Figure 2. Schematic diagrams of j e t flow 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 at various d i s t a n c e s from o r i f i c e . From Szekely and Themelis (85). 16 region the flow 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 there i s no longer a c e n t r a l core of constant values. 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 other parameters approach ambient valu 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 at va r i o u s d i s t a n c e s from the nozzle are i l l u s t r a t e d i n Figure 3. I f these pro-f i l e s are expressed 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 of the c e n t e r l i n e value at each c r o s s - s e c t i o n , a l l the curves w i l l c o i n c i d e , as shown i n Figu r e 4. S i m i l a r p r o f i l e s may be drawn f o r dimensionless temperature and dimensionless c o n c e n t r a t i o n . Abramovich (61) and S c h l i c h t i n g (62) provide comprehensive treatments of t u r b u l e n t j e t theory and boundary l a y e r theory r e s p e c t i v e l y and are recommended fo 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 v e l o c i t y p r o f i l e s i n r a d i a l s e ctions at d i f f e r e n t distances (X) from o r i f i c e . From Szekely and Themelis (85). •o — o X=0.2M • X=0,35M * J: =0.50 M © x-0.60M A J:=0,75M -4^ #f ^ IS £ Figure 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). 00 19 1 . 2 . 3 - 2 J e t Cone Angle Once the j e t flow becomes f u l l y developed, the outer envelope of the j e t expands c o n i c a l l y , as though the j e t were issued from a point source l o c a t e d at the apex of the cone, or the " j e t pole" (Figure 2 ). The included angle of t h i s cone, known as the j e t cone angle, i s a v i t a l parameter of 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 of the degree t o which the j e t i n t e r a c t s w i t h the ambient f l u i d , an important aspect of i t s heat, 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 , then, t h a t many i n v e s t i g a t o r s have attempted to measure t h i s parameter as a f u n c t i o n of the 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 the j e t expanded at a cone angle of 1 4 ° . Pabst and Bohl (64) studied the mixing of a coal-gas j e t w i t h s t a t i o n a r y a i r and found t h a t the j e t expanded more q u i c k l y than a s i m i l a r a i r j e t i n a i r , while C o r r s i n and Uberoi (65) determined, by blowing a hot a i r j e t i n t o c o o l a i r , t h a t a r e d u c t i o n i n the d e n s i t y of the j e t r e l a t i v e to the r e c e i v i n g medium increases the r a t e of spread. Rawn and Palmer ( 6 7 ), studying the extent of sewage d i s t r i b u t i o n i n sea water, measured the cone angle of 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 Singer (66) studied a i r / a i r , water/ water, sugar solution/sugar s o l u t i o n , and hydrogen-into-a i r j e t s , and measured cone angles of between 14° and 24.5°, wi t h t h a t f o r the water j e t being 14° and f o r the a i r j e t , 20°. On the b a s i s of these r e s u l t s they proposed the 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 0 , 1 3 3 (1.5) i n which the cone angle i s a f u n c t i o n only of the kinematic v i s c o s i t y of the j e t f l u i d . Since the 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 to the kinematic v i s c o s i t y , they conclude that an increase i n the Reynold's number produces a decrease i n the j e t angle. 21 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 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 of the j e t f l u i d or of a f l u i d of s i m i l a r d e n s i t y , the j e t penetrates u n t i T i t s eventual decay along a s t r a i g h t l i n e known as the j e t t r a j e c t o r y . In t h i s case of a constant-density j e t , the 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 the nozzle c e n t e r l i n e and i s the geometric center of the j e t as w e l l as the locus of p o i n t s of gr e a t e s t v e l o c i t y . I f , however, the 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 medium of, say, greater d e n s i t y than the j e t f l u i d , the j e t tends to r i s e due to the d e n s i t y d i f f e r e n c e between the two f l u i d s . In t h i s case the t r a j e c t o r y which best describes the path of the j e t f i r s t emerges tangent to the nozzle c e n t e r l i n e but then curves upwards to l i e c e n t r a l l y w i t h i n the j e t envelope. Horn and Thring (68) i n v e s t i g a t e d the e f f e c t of de n s i t y d i f f e r e n c e s on thepath of 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 that the j e t cone angle was not a f u n c t i o n of the magnetite-to-water d e n s i t y r a t i o and that the j e t t r a j e c t o r y would most s u i t a b l y be placed symmetrically w i t h i n the j e t envelope. A dimensionless expression was then developed to describe the v e r t i c a l displacement of the j e t a x i s as a f u n c t i o n of 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 Thring (69) derived a more complex expression f o r the 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 conserved, and that the 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 e f f l u e n t c oncentration 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 magnetite-water system was used to t e s t the p r e d i c t i o n s . Abraham (70) determined t h a t the curvature 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 to the d e n s i t y d i f f e r e n c e between the j e t f l u i d and the ambient medium depends on the magnitude of the modified Froude number, N^ r , w i t h large curvature corresponding to small values of Kr 1.2.4 Gas J e t s i n L i q u i d s - Heterogeneous J e t s 1.2.4.1. 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 the concepts p r e v i o u s l y considered: - bubble formation, break-up and coalescence - bubble r i s e behaviour and shape - d i s t r i b u t i o n of v e l o c i t y , temperature and gas co n c e n t r a t i o n between a c e n t r a l core and an outer boundary - c o n i c a l expansion at an angle which i s i n some way dependent upon the j e t system. - t r a j e c t o r y curvature due to buoyancy f o r c e . 23 as well as the added complications that gas concentration does not vary continuously, but i n discrete pockets or bubbles, and that the je t i s instantaneously unstable and i s constantly f l u c t u a t i n g . If the j e t i s viewed over a period of time, however, i t can be seen that the j e t envelope fluctuates about a mean value and that the time-averaged gas concentration does vary continuously. It i s through the technique of time-averaging that many of the concepts developed for the case of homogeneous jets may be adopted to f a c i l i t a t e the description of heterogeneous j ets. 1.2.4.2 Previous Work In 1940 Kazanstev (71) studied the mechanics of a gas j e t i n a Bessemer bath using an air-mercury system. Although primarily concerned with the degree of metal ejection from the bath he determined that the a i r j e t in mercury i s i n the form of metal droplets dispersed i n the gas. The operating conditions i n these tests are not clear, however, and i t i s not ce r t a i n that the experimental method i s r e l i a b l e . He concluded that small diameter nozzles at deep submergence would provide optimum operation with reduced metal ejection. Deev et a l (72) measured l i q u i d entrainment through the gas outlet of a model converter. In the course of 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 best mixing i n the bath i s obtained by d i r e c t i n g the tuyeres h o r i z o n t a l l y or upwards at a small angle. 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 the most important 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 the d e o x i d a t i o n of 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 bath. Gas phase c o n t r o l p r e v a i l e d at melt concentrations above 0.1 percent oxygen, and k g C ' , the product of 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 ( k g ) and the s p e c i f i c i n t e r f a c i a l area ( < 0 was constant w i t h d i s t a n c e along the 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 number (Re Q) i n the range 1000< Re 0 <9100. They a l s o note that a t r a n s i t i o n occurs between the cone zone of the j e t and a column zone of n e a r l y constant c r o s s - s e c t i o n i n which the v e l o c i t y of the g a s - l i q u i d d i s p e r s i o n may be assumed to be constant. In 1969 Themelis et a l (74) derived an equation 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 i n j e c t e d i n t o a l i q u i d on the b a s i s of c o n t i n u i t y and momentum balance r e l a t i o n s h i p s , a l l o w i n g the j e t r i s e under the i n f l u e n c e of buoyancy. The cone angle of the j e t was measured at 20° f o r the air-water system, and w i t h t h i s value the t h e o r e t i c a l equation showed good agreement w i t h photographic measurements of an a i r j e t i n water. 25 The model was used to d e s c r i b e the j e t t r a j e c t o r y i n a copper converter w i t h the supporting argument t h a t "agreement between theory and experiment f o r a system where the 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 the case of an a i r j e t i n l i q u i d matte or copper." Nemchenko et a l (75) measured the cone angle of a n i t r o g e n j e t i n water to be 23°. This value was considered t o be a p p l i c a b l e t o l i q u i d metal systems and the hydrodynamics of the l a d l e degassing of s t e e l were di s c u s s e d through c a l c u l a t i o n . An equation was presented to d e s c r i b e 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 ; the c o e f f i c i e n t s were e m p i r i c a l l y obtained. The authors concluded t h a t n o z z l e s d i s t r i b u t e d throughout the 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 bubbles would r e s u l t i n f a r more e f f i c i e n t gas usage than j e t s . N e i t h e r the problems of n o z z l e - p l u g g i n g at low f l o w r a t e s nor the economics of a slow-bubbling process were d i s c u s s e d . In 1971, Wraith (76) reported an a i r - w a t e r model study on gas l a n c i n g . 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 mixing along the t r a j e c t o r y . A s o n i c j e t i n j e c t e d downward at 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 than a 2 6 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 "the d i f f e r e n c e s i n j e t behaviour between water and l i q u i d metals, p a r t i c u l a r l y regarding p e n e t r a t i o n d i s t a n c e , l i m i t the relevance of the water model." Spesivtsev and S t r e k a l o v s k i i (77) noted the p u l -s a t i n g nature of the j e t as w e l l as the observation t h a t immediately at the p o i n t of i n j e c t i o n the j e t i s widened by three to four times. 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 equation i s proposed d e s c r i b i n g the h o r i z o n t a l length 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 to be i n reasonable agreement w i t h experimental data obtained from gas-water,-ZnCl 2 s o l u t i o n , and - T h o u l e t 1 s 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 wi t h r e s u l t s of t e s t s i n the a i r -mercury system. Spesivtsev et a l (78) c l a i m t h a t i n isothermal models the f a c t o r which determines 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 . Surface t e n s i o n and v i s c o s i t y of the l i q u i d are s a i d t o have an e f f e c t i n some cases, but t h i s i s not w e l l defined yet. The authors 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 melts 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 to t h a t observed i n the gas-mercury system. Unfortunately they do not elaborate on t h i s i n more d e t a i l . 27 Igwe et 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 , bubble 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 the nitrogen-water system as a f u n c t i o n of nozz l e s i z e and desig n , gas d r i v i n g pressure, and l i q u i d d e n s i t y . For h o r i z o n t a l gas i n j e c t i o n they 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, given by the product of the gas d r i v i n g pressure and the nozzle diameter. In 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 of 2 .25 g/cm3 the 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 i n c r e a s e s . Brimacombe et a l (80) explored aspects of 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 of 1 percent SO2 i n j e c t e d i n t o an aqueous s o l u t i o n of 0 .3 percent hydrogen peroxide. From the measured a b s o r p t i o n r a t e s , and u s i n g the t r a j e c t o r y equation of Themelis e t a l ( 7 4 ) , values of the product of the 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 of 1 t r a j e c t o r y , k g Q 2 " , were d e r i v e d . For a given o r i f i c e diameter, the r a t i o of k s 0 2 ' t o ^ a s f-*- o w r a t e was found to be independent of o r i f i c e Reynold's number. Regions of l i q u i d phase c o n t r o l , consecutive c o n t r o l , and gas-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 suggested t h a t a submerged gas j e t i n a l i q u i d i s composed of 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 l i q u i d are dispersed i n a continuous gas phase, and the second zone c o n s i s t i n g of gas bubbles i n a continuous l i q u i d -phase, caused by the l i q u i d fragments i n the f i r s t zone c o l l i d i n g and c o a l e s c i n g downstream. In a d d i t i o n , he suggests t h a t the surface t e n s i o n of the l i q u i d might w e l l be the important parameter i n the dynamics of such j e t s . However, no evidence i s o f f e r e d t o support e i t h e r of these p o s t u l a t e s . Tien and Turkdogan (82) have a l s o proposed a three zone model of a gas j e t i n a l i q u i d . The f i r s t zone c o n s i s t s of a gas pocket c o n t a i n i n g dispersed l i q u i d phase and p e r s i s t s f o r 28 nozzle diameters downstream. In the second zone the gas stream transforms to gas bubbles and i n the t h i r d zone the bubbles grow u n t i l the 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 that 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 of 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 surface t e n s i o n of the l i q u i d , but i s independent of the o r i f i c e diameter. The entrainment of l i q u i d by bubbles i s s a i d to be d i r e c t l y p r o p o r t i o n a l 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 reported 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 both h o r i z o n t a l l y and v e r t i c a l l y upwards i n t o water. He claims t h a t at s u f f i c i e n t l y high pressure there i s no back-penetration and the j e t diameter at the o r i f i c e equals the o r i f i c e diameter. Both forward and back p e n e t r a t i o n of the j e t s are expressed 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 root of the Froude number. 30 CHAPTER 2 OVERVIEW OF THE PRESENT WORK I t i s apparent from an examination of the e x i s t i n g l i t e r a t u r e t h a t very l i t t l e i s known of the behaviour of submerged gas j e t s i n l i q u i d s and f u r t h e r , because of 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 d e t a i l e d d e s c r i p t i o n of the p h y s i c a l c h a r a c t e r i s t i c s of submerged gas j e t s i n l i q u i d metals. This work has been d i r e c t e d toward the study of an is 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 metal system by the d i r e c t measure-ment of the p h y s i c a l c h a r a c t e r i s t i c s of 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. The a i r - w a t e r system has a l s o been i n v e s t i g a t e d p r i m a r i l y as an accessory to a s s i s t i n the understanding of the air-mercury system. The main o b j e c t i v e s of the present work were as f o l l o w s : (i) To present a d e t a i l e d d e s c r i p t i o n of a 3-dimensional 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 i n c l u d e s b a s i c observations of the 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 of gas volume f r a c t i o n and bubble frequency throughout the j e t . 31 ( i i ) To study the e f f e c t of tuyere diameter and Froude number on the shape of the j e t and on the 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 bubble frequency. ( i i i ) To d e f i n e important p r o p e r t i e s of the system such as j e t cone angle, j e t t r a j e c t o r y , 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 j e t diameter and to d i s c u s s t h e i r s i g n i f i c a n c e as c h a r a c t e r i s t i c parameters of a gas j e t - l i q u i d metal system. The e f f e c t s o f Froude number and tuyere diameter upon these parameters were studied i n the air-mercury system. (iv) To describe the p h y s i c a l process 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 the 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 i n t e r e s t . (v) To assess 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 such as d e n s i t y , v i s c o s i t y , and surface t e n s i o n i n terms of t h e i r i n f l u e n c e upon j e t behaviour. (vi) F i n a l l y , to r e l a t e the r e s u l t s of s t u d i e s i n the air-mercury system to i n d u s t r i a l copper converting and steelmaking systems and to 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 operations i n terms of the present experimental r e s u l t s . 32 CHAPTER 3 APPARATUS AND PROCEDURES 3.1 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. Submerged a i r j e t s were 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 of mercury through an interchangeable s t r a i g h t -bore nozzle. Time-averaged, poi n t values of gas volume f r a c t i o n and bubble frequency were measured as a f u n c t i o n of 3-dimensional p o s i t i o n i n the bath by means of 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 to the b a s i c apparatus allowed the attempted measurements of gas v e l o c i t y and back-penetration of mercury i n t o the nozzle. 33 3.1.1 P h y s i c a l Apparatus The apparatus employed i n the study of a i r - i n -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 Figure 5. I t c o n s i s t e d of a converter-shaped 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 to supply c l e a n , dry a i r to the tuyere, an e l e c t r o r e s i s t i v i t y probe to i n t e r c e p t and sense the gas bubbles at v a r i o u s points i n the bath, and e l e c t r o n i c apparatus to measure and record the information received at the probe t i p . Electronic Apparatus Including Integrator and Counter Electroresistivity Probe Mercury Tank Air From Compressor i j Cyclone F i g u r e 5 Air Supply System Schematic of apparatus employed i n the study of air-mercury j e t s . 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 to the tuyere by a compressor 5 N 2 maintaining a gauge pressure of 6.9 x 10 /M (100 p s i g . ) ; the pressure was 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 flow c o n t r o l was e f f e c t e d by a needle v a l v e . The a i r was passed through a cyclone-type c e n t r i -f u g a l separator and s t r a i n e r and then through a f i v e micron f i l t e r to remove o i l , condensed water, and s o l i d p a r t i c u l a t e . Flow c o n d i t i o n s near the tuyere were monitored by a rotameter, symmetrically flanked by two Bourdon-type pressure gauges. The readings of the two pressure gauges were averaged to determine the pressure w i t h i n the rotameter, a l l o w i n g mass flow 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 . (Before use, a l l flow meters were c a l i b r a t e d independently by two d i f f e r e n t methods, and were then cross-checked against each other as a f i n a l insurance against e r r o r ) . Gas flow at the tuyere e x i t was c a l c u l a t e d f o r the c o n d i t i o n of atmospheric pressure plus mercuro-static head at that p o i n t . .3.1.1.2. The Mercury Tank The mercury was contained i n a converter-shaped v e s s e l made of 40.6 cm I.D. carbon s t e e l pipe, cut 25.4 cm.long and sealed with 1.9 cm.- t h i c k p l e x i g l a s s end-36 pieces (Figures 6 & 7). H o r i z o n t a l b a f f l e s were fastened to the p l e x i g l a s s w a l l s to prevent j e t d e f l e c t i o n due to s l o p p i n g , and the c y l i n d r i c a l tank was truncated 8.9 cm. above i t s h o r i z o n t a l diameter t o allow the f i x t u r e of t r a v e r s i n g equipment. In a con-f i g u r a t i o n s i m i l a r to copper converter p r a c t i c e , a h o r i z o n t a l interchangeable tuyere was Inserted through the side w a l l of the tank, located c e n t r a l l y between the p l e x i g l a s s end-pieces and 15.2 cm. below the h o r i z o n t a l diameter. U n l i k e converter p r a c t i c e , however, the tuyere extended i n t o the bath (up t o 10.2 cm.) t o reduce the i n f l u e n c e of the rear w a l l upon the j e t c o n f i g u r a t i o n . The bath was f i l l e d w i t h mercury to a height of 9.1 cm. above the tuyere 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 a 3-dimensional, orthogonal, graduated t r a v e r s i n g system which r i g i d l y held the e l e c t r o r e s i s t i v i t y probe and allowed accurate p l a c e -ment of the probe t i p at any p o i n t i n the bath. The tank was enclosed w i t h a l a r g e p l a s t i c bag and the o f f -gas was forced to pass through a granulated sulphur f i l t e r to remove any mercury vapour before f i n a l discharge to atmosphere through a fume hood. 1-9 cm. thick Figure 6. Schematic of mercury tank 38 F i g u r e 7. Photographs of the c o n v e r t e r - t y p e tank and a n c i l l a r y a pparatus used i n the a i r - m e r c u r y t e s t s . 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 Since mercury i s an opaque f l u i d i t was necessary t o design a probe which could "see" i n t o the bath and measure p o i n t - v a l u e q u a n t i t i e s of gas volume f r a c t i o n and bubble frequency. 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 8. The probe was a l e n g t h of m i l d s t e e l welding rod which was turned to a needle-point and then cleaned and degreased w i t h cholorethene. The surface was then dip-coated w i t h a t h i n l a y e r of red G l y p t o l (a General E l e c t r i c i n s u l a t i n g f i n i s h ) and baked at 4 0 0 K f o r 2 hours; t h i s procedure was repeated 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 developed. An i n s u l a t e d copper w i r e was soldered i n t o a hole p r e v i o u s l y d r i l l e d i n t o the top of the r o d , and the rod 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 the s t a r t of the needle-taper t o beyond the s o l d e r j o i n t and over the i n s u l a t e d copper w i r e . For r i g i d i t y the assembly was 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 was roll-compressed near each end t o g r i p the rod 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 . F i n a l l y the G l y p t o l c o a t i n g was r e t i c u l a t e d from the t i p of the rod using S t r i p - X , a commercial s o l v e n t marketed by G.C. E l e c t r o n i c s , l e a v i n g a bare s t e e l p o i n t .08 cm. long 40 Roll-compressed To Grip Securely Mild Steel Rod Tapered To A Needle-point Baked-on Glyptol Over The Entire Rod Insulated Copper Wire Heat Shrinkable Spaghetti-tubing Mild Steel Sheath Silicone Sealant Exposed Steel Tip Figure 8. 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. at i t s l a r g e s t diameter. The probe used i n t h i s work i s s i m i l a r t o one which was f i r s t employed by Neal and Bankoff (84) f o r the measurement of l o c a l v o i d p r o p e r t i e s i n a mercury-n i t r o g e n two-phase flow system. In the present work, however, the probe had t o be more mobile to enable sampl-i n g of a l a r g e r volume yet at the same time i t had t o be much more r i g i d t o endure the b u f f e t i n g of the h i g h -v e l o c i t y a i r j e t without d e f l e c t i n g from i t s sampling p o i n t . 3.1.2. E l e c t r o n i c Apparatus I t was mentioned e a r l i e r t h a t the e l e c t r o r e s i s t i v i t y probe was designed t o "see" i n t o the bath, t o sense the 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 accomplished by des 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 the probe t i p and the s t e e l w a l l s of the mercury tank as e l e c t r o d e s , coupled by the mercury i n the tank. When the probe t i p contacted mercury the c o u p l i n g was complete, however, when . an a i r bubble surrounded the probe t i p the c i r c u i t was broken. The e l e c t r o n i c apparatus 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 of a power supply which caused a Probe 800 & V \ A A Bounceless Switch L +5V DC Reg Power Supply Timer 33 a A A A A Integrator Counter 7IMW N3 F i g u r e 9. S c h e m a t i c o f e l e c t r o n i c a p p a r a t u s employed i n t h e s t u d y o f a i r - m e r c u r y j e t s . 43 c u r r e n t to flow whenever the 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 the f r a c t i o n of time d u r i n g which c u r r e n t was f l o w i n g , or volume f r a c t i o n mercury, and a counter t o count the number of c i r c u i t i n t e r r u p t i o n s , or bubble frequency. A timer connected t o a bounceless s w i t c h allowed a l l the e l e c t r o n i c equipment t o be s t a r t e d and stopped simultaneously. 3.1.2.1. The Integrator. The i n t e g r a t o r i n the c i r c u i t was designed and b u i l t t o measure the t o t a l time d u r i n g which the c i r c u i t was c l o s e d , i . e . the time dur i n g which the probe t i p was c o n t a c t i n g mercury. The sample time was chosen s u f f i c i e n t l y l a r g e t h a t t h i s value could be normalized t o read volume f r a c t i o n mercury. By d i f f e r e n c e , the volume f r a c t i o n of gas a t the sample p o i n t was determined. 3.1.2.2. '-The Counter The counter was connected p a r a l l e l t o the inte:-g r a t o r t o record the volt a g e pulses caused by c i r c u i t i n t e r r u p t i o n s . I t was determined t h a t a bubble i n t e r -c e p t i n g the probe t i p and breaking the c i r c u i t caused a p o s i t i v e v o l t a g e pulse across the i n t e g r a t o r , w h i l e a bubble l e a v i n g the probe t i p and c l o s i n g the c i r c u i t caused a negative vo l t a g e p u l s e . A Hamner s c i n t i l l a t i o n 44 counter was modified to 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) but to ignore each negative pulse. In t h i s manner each bubble which i n t e r c e p t e d and enveloped the probe t i p was counted only once. When d i v i d e d by the sample time, t h i s t o t a l count y i e l d e d a value of bubble frequency. 3.1.2.3 The Timer A timer was preset to the d e s i r e d sample time and connected to c o n t r o l a bounceless switch on the primary c i r c u i t . Thus, by a c t u a t i n g the timer both the i n t e g r a t o r and counter were set i n t o o p e r a t i o n , and at the end of the d e s i r e d sample time both 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 bounceless switch/power supply u n i t and the i n t e g r a t o r , both of which were designed and b u i l t i n the e l e c t r o n i c s shop of the Metallurgy Department, are included as Appendix I. 3.1.3. General Operating Procedure The timer was preset to a sample time of 58 seconds, the probe was p o s i t i o n e d to sample the d e s i r e d p o i n t i n the bath, and the a i r flow was adjusted and allowed to 45 s t a b i l i z e . The timer was then 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 swit 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 the i n t e g r a t o r and counter to. begin re c o r d i n g . At the end of the p r e s c r i b e d 58 seconds, the timer a u t o m a t i c a l l y caused the bounceless switch t o open, thus stopping the i n t e g r a t o r and counter. Values were recorded. The gas volume f r a c t i o n and bubble frequency were measured at 2000 to 3000 data p o i n t s per run, p r o v i d i n g a high d e n s i t y 3-dimensional map of the j e t . Runs were made fo r tuyere diameters of 0.325 cm. and 0.476 cm., over a range of modified 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 were a l s o attempted. For t h i s purpose a d d i t i o n a l equipment was added to the above-mentioned apparatus. A s o l e n o i d valve was added to the a i r l i n e immediately behind the tuyere and a storage o s c i l l o s c o p e was connected i n p a r a l l e l to the i n t e g r a t o r and counter. S u i t a b l e switches were designed and connected such t h a t by t r i g g e r i n g the timer the so l e n o i d v a lve was a u t o m a t i c a l l y c l o s e d , s h u t t i n g o f f the a i r supply, and simultaneously 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 o s c i l l o s c o p e 4 6 recorded a square-wave " b l i p " each time a bubble passed the probe t i p , and i t was intended that by measuring the time from a i r supply interrupt to the l a s t bubble passing the probe, knowing the position of the probe t i p , an average v e l o c i t y could be determined for various regions of the j e t . Since both bubble frequency and gas volume f r a c t i o n were measured, the additional information on gas v e l o c i t y would enable bubble size to be calculated. 3.1.5. Measurements of Mercury Backflow Into the Tuyere For reasons to be discussed l a t e r there was thought to be a strong p o s s i b i l i t y of mercury backflow into the tuyere. In an attempt to detect t h i s behaviour the nozzle i l l u s t r a t e d i n Figure 10 was designed. Two such nozzles •were constructed, one of 0.325 cm. I.D. and the other of 0".4'76 cm. I.D. Both nozzles were of roughly the same ov e r a l l length as the regular tuyeres, but i n t h i s case the l a s t 7.5 cm. or so was made of t e f l o n . This allowed two lengths of nick e l wire to be Inserted through the nozzle wall, protruding into the bore near the nozzle e x i t . Each of these wires acted independently i n the same function 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 at a time, connected into the c i r c u i t detailed e a r l i e r , replacing the probe. In t h i s case, however, intere s t was directed to measuring the f r a c t i o n of time during which F i g u r e 10. S e c t i o n a l d i a g r a m o f t e f l o n n o z z l e u s e d i n t h e d e t e r m i n a t i o n o f m e r c u r y b a c k f l o w . 4>-48 the n i c k e l sensor was i n contact w i t h a wave of mercury as w e l l as the frequency w i t h which t h i s backflow occurred. T h is t e s t , of course, r e q u i r e d the mercury wave be continuous w i t h the bath, as the second e l e c t r o d e was s t i l l the bath w a l l . To a l l o w the measurement of non-continuous splashes of mercury both sensors were connected as e l e c t r o d e s (one of them r e p l a c i n g the tank w a l l i n t h i s f u n c t i o n ) . This permitted the d e t e c t i o n of any mercury 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 of Equipment Performance There were two primary areas of concern r e g a r d i n g equipment performance. One was t h a t the e l e c t r o n i c response to a bubble breaking or c l o s i n g the c i r c u i t should be f a s t and c l e a n ; the other was t h a t the counter should count each i n t e r c e p t i n g bubble once and o n l y once. The f i r s t aspect, t h a t of the c i r c u i t r y response, was t e s t e d by viewing on a storage o s c i l l o s c o p e the waveform produced by a bubble i n t e r c e p t i n g and then l e a v i n g the 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 of such a bubble i s shown i n F i g u r e 11. A l l wave corners are s t i l l sharp i n d i c a t i n g t h a t the break time 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 of 2 msec, per major d i v i s i o n . F i g u r e 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 of f i v e bubbles i n t e r -49 Figure 11. A voltage pulse recorded at a trace speed of 2 ms./division, or 500 cm./s 50 Figure 12. Five f a s t voltage pulses viewed at a tr a c e speed of 1 m s / d i v i s i o n , or 1000 cm/s. 51 cepting and passing the probe t i p i n quick succession. The t r a c e speed i n t h i s case i s twice that of Figure 11. I t i s worth n o t i n g t h a t bubbles of t h i s s m a ll s i z e were s t i l l p i e r c e d by the probe. The second area of concern, t h a t the counter should count each bubble once and only once, was t e s t e d by the use of a dual-channel storage o s c i l l o s c o p e . One channel was connected to the counter such t h a t i t d i s p l a y e d a b l i p each time the counter r e g i s t e r e d a bubble; the other channel was connected as i n the previous t e s t to d i s p l a y the waveforms of passing bubbles. The t r a c e s of both channels were synchronized and t r i g g e r e d simultaneously, and t y p i c a l r e s u l t s are shown i n Figure 13. I t can be seen t h a t each and every negative voltage pulse was r e g i s t e r e d by the counter, and t h a t the counter i n f a c t counted each i n t e r c e p t i n g bubble once and only once. (The voltage waveform fed to the o s c i l l o s c o p e was i n v e r t e d . In fact the b l i p occurs at each p o s i t i v e pulse as st 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 of the op e r a t i o n of the counter.) 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 to some extent, but was one which could not p r a c t i c a l l y be improved. I t i s expected t h a t bubbles i n the s i z e range of 0.1 cm. or l e s s were probably d e f l e c t e d . Figure 13. O s c i l l o s c o p e traces showing voltage pulses caused by bubbles passing the p r o b e - t i p , w i t h corresponding counte r - b l i p s above. 53 3.1.7 S t a t i s t i c a l Evaluation of Data Reproduceability. Since a l l the measurements were time-averages of fluctuating point values i t was necessary to test the s t a t i s t i c a l accuracy and reproduceability of the r e s u l t s . The r e s u l t s of such tests are summarized i n Table I. Both the integrator readings (percent air) and the counter readings (bubbles per second) were evaluated at three d i f f e r e n t count rates, chosen to represent the range actually encountered during experimental runs. The sampling accuracy i s good with the standard deviation being low and approximately constant. 54 MEAN STANDARD VALUE DEVIATION S ( X ) ( S ) -% AIR 0.5 1% HIGH COUNT RATE 80 MEDIUM COUNT RATE 21 1.2 6% LOW COUNT RATE 7 i . i 16% BUBBLES PER SECOND 75 3.4 5% HIGH COUNT RATE 16 1.1 7% MEDIUM COUNT RATE 4 0.8 20% LOW COUNT RATE each value i s based on a sample s i z e of 50 t e s t s TABLE I . STATISTICAL EVALUATION OF SAMPLING ACCURACY. 55 3.2 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 Into Water 3.2.1 P h y s i c a l Apparatus The tank used f o r t h i s work was a rec 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 , straight-bore, s t a i n l e s s s t e e l tuyeres were c e n t r a l l y l o c a t e d through the narrow s i d e w a l l , at l e a s t 10 cm. above the tank bottom. The a i r supply was by compressed a i r c y l i n d e r s and once again the flow was monitored by a rotameter, symmetrically flanked by pressure gauges. 3.2.2 Elapsed-Time Photography Time exposures ( u s u a l l y 5s..prl2s.) of the gas j e t i n water were taken w i t h a p l a t e camera f o r a v a r i e t y of operating c o n d i t i o n s . The bath was i l l u m i n -ated 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 the photographed j e t appeared dark against a l i g h t back-ground. Both the i n i t i a l cone angle 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 to be the geometric centre of the j e t and was c a l c u l a t e d i n each case from the measured envelope. 56 It was suspected that elapsed-time photography might be a more f l e x i b l e measuring device than previously indicated by other workers. To te s t t h i s p o s s i b i l i t y a j e t was photographed over a range of exposure times at various lens settings, and each negative was printed over a range of exposure times at various lens settings. The appearance of the j e t was compared over the range of photographic and p r i n t i n g conditions. (For the purposes of obtaining data, a good pr i n t was considered to be that which maximized the apparent size of the j e t envelope but yet maintained sharp contrast 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-fi g u r a t i o n , the photographic and p r i n t i n g conditions necessary to meet these c r i t e r i a were constant.) 3.2.3 Jet Determination by E l e c t r o r e s i s t i v i t y Probe Horizontal a i r jets 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 largely for the purpose of comparison with photographic measurements. I n i t i a l l y , problems were encountered i n making the water ele c t r i c a l l y - c o n d u c t i n g while eliminating electrode reactions which tended to insulate the exposed probe t i p . The solution was found i n adding very small amounts (to less than 0.1%) of HNO^ to de-ionized and f i l t e r e d water, while using copper-tipped probes. 57 As i n the mercury t e s t s the moveable probe was mounted on a 3-dimensional orthogonal t r a v e r s i n g system which was graduated to enable the co-ordinate p o s i t i o n of the probe i n the bath to be read at any p o i n t . In t h i s case, however, the e l e c t r o n i c apparatus was not as s o p h i s t i c a t e d as t h a t used i n the mercury work. The average current at each p o s i t i o n was determined by means of a m i l l i v o l t m e t e r connected across 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 output from the m i l l i v o l t m e t e r was damped through an RC c i r c u i t w i t h a time-constant of approximately 2 seconds and then fed to a chart recorder. The recorder 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 the " c l o s e d - c i r c u i t " reading obtained when the moveable probe was outside the j e t envelope. This reference value was rechecked many times d u r i n g each run t o ensure constant 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 of maximum volume f r a c t i o n gas was determined as the locus of p o i n t s having the lowest average current readings (as measured by the m i l l i v o l t m e t e r ) . The envelope of the j e t was determined by current readings w i t h i n one percent of the " c l o s e d - c i r c u i t " reference value. 58 3.2.4 High-speed Cinematic 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 i n t o water were photographed a t a f i l m speed of 250 frames per second by means of a Hycam high-speed camera. Blowing c o n d i t i o n s were v a r i e d to cover a range of m o d i f i e d Froude 2 3 numbers from 5 x 10 t o 6 x 10 at a constant n o z z l e diameter of 0.3 cm. 3.2.5 Slug-flow Measurements S t i l l photographs of a i r j e t s i n water (Figure 14) revealed the presence of l a r g e bubbles which rose prematurely, o u t s i d e the j e t envelope. Since these l a r g e bubbles or "s l u g s " would reduce, i n e f f e c t , the volume f l o w r a t e of gas i n the main j e t and could s i g n i f i c a n t l y lower the 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 gas-l i q u i d mass t r a n s f e r , i t was decided t o t r y t o measure the f r a c t i o n of the gas flow which i s spent i n s l u g formation. Catch boxes, open at the bottom and w i t h a flowmeter p o s i t i o n e d on the top e x i t hole (Figure 15) were submerged about one or two centimeters i n the water and p o s i t i o n e d across the tank i n a g r i d sequence. (Figure 15a). F i g u r e 14. S t i l l photograph of an a i r j e t i n water (Re= 38,400) showing slugs. Figure 15. Photograph of a "catch box" used i n the measurement of s l u g flow. 61 intersection of jet envelope with water surface water surface t a n k b o u n d a r y grid interval corresponding to catch - box position Figure 15a. I l l u s t r a t i o n of catch-box placement i n the measurement of the slug-flow. 62 It was hoped that in t h i s manner r e l a t i v e gas flow rates leaving the d i f f e r e n t sectors of the tank could be established, giving 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 lay outside 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 data d e r i v e d from the air-mercury system were obtained by sampling v a r i o u s p o i n t s w i t h i n the bath by means of the 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 across the j e t y i e l d e d a gas co n c e n t r a t i o n p r o f i l e and a bubble frequency p r o f i l e s i m i l a r t o those i l l u s t r a t e d i n Figures 16 and 17. A one-dimensional t r a c e such as t h i s , however, i s of s i g n i f i c a n t value only when i t passes through the c e n t e r l i n e or t r a j e c t o r y of the j e t . Since an aim of this"work was t o completely d e s c r i b e the gas d i s t r i b u t i o n at a l l p o i n t s i n the j e t , i t was thought that the data could best be represented as a s e r i e s of contour p l o t s on mutually orthogonal planes. A complete d e s c r i p t i o n of the 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 at four sets of operating c o n d i t i o n s described i n Table I I . The gas volume f r a c t i o n and bubble frequency d i s t r i b u t i o n s were d i r e c t l y measured at 2000 t o PROBE POSITION ( cm ) Figure 16. Probe t r a c e through an air-mercury 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 Figure 17. Probe trace through an air-mercury j e t showing bubble frequency p r o f i l e . Run No. Np r do (cm.) u Q (Mach.) 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 TABLE I I . Operating c o n d i t i o n s t e s t e d i n the air-mercury system. 67 3000 data 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 the j e t . These p o i n t s were chosen to l i e on a 3-dimen-s i o n a l g r i d of h o r i z o n t a l and v e r t i c a l planes, 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 Figure 18. The nozzle e x i t was l o c a t e d at coordinates (0,0,0) and the planes were l a b e l l e d according to t h e i r d i s t a n c e from the nozzle e x i t , as shown i n Figure 18. A computer was programmed to accept the data and t o produce a contour map of the data values on each plane. This program i s l i s t e d i n Appendix I I . 4.1.1 Volumetric Gas D i s t r i b u t i o n W i thin the J e t A t y p i c a l contour map of volume percent a i r , obtained 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 Figure 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 plane l y i n g 1.3. cm.above the tuyere c e n t e r l i n e from Run HG1. The contour values range from 70 volume percent a i r near the center to the 1 percent a i r contour which was chosen to d e f i n e the outer boundary of the j e t . Figure 20 i l l u s t r a t e s the contour map of a v e r t i c a l plane f o r the same operating c o n d i t i o n s as i n Figure 19 (Run HG 1). In t h i s case the plane i s X=0, F i g u r e 19. Contour nap of volume percent a i r f o r the plane 3 = 1.3 of run HG 1. F i g u r e 2 0 . C o n t o u r map o f v o l u m e 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 1. 71 the plane p a r a l l e l to and b i s e c t i n g the tuyere. Contour values range from 80 percent a i r near the nozzle e x i t to 1 percent a i r at the outer boundary. The p o s i t i o n of the tuyere has been i l l u s t r a t e d on the map, and the j e t t r a j e c t o r y , represented by a bold l i n e , has been drawn through the po i n t s corresponding t o maximum gas conce n t r a t i o n . Figures 21 t o 26 i l l u s t r a t e the corresponding contour maps obtained at the operating c o n d i t i o n s of runs Hg 2, 3, and 4. To give a f u l l p i c t u r e of one of the j e t s , a complete set of volume percent a i r contour maps fo r run Hg 1 i s given i n Appendix I I I . 4.1.2 Bubble Frequency D i s t r i b u t i o n Figures 27 and 28 show the contour maps of bubble frequency f o r run Hg 1 on the same planes (& = 1.3 and X=0) as chosen t o i l l u s t r a t e the gas d i s t r i b u t i o n . The bubble frequencies range from 1 at the j e t envelope t o greater than 100 bubbles per second i n the core. Figures 29 through 34 s i m i l a r l y show the bubble frequency d i s t r i b u t i o n measured i n runs Hg 2, 3 and 4. A complete set of bubble frequency contour maps f o r run Hg 1 i s included, as Appendix IV. o 3 F i g u r e 22. C o n t o u r 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 2. -S.D H O R I Z O N T A L D I S T A N C E PERPEND ICULRR T O N O Z Z L E IN C M -4.0 -3.0 -2.D -J.D 0.0 1.0 2.0 3.0 _l I I 1 1 1 ——•—I L. 4.0 5.0 i _ 1L Run HG 4 Volume % Air N'Fr = 203 d 0 - 0.476 cm F i g u r e 25. Contour map of volume percent a i r f o r the plane St = 1.3 of run HG 4. ON Figure 26. Contour map of volume percent a i r f o r the plane X = 0 of run HG 4. " i Run HG I Bubbles Per Second • i-!.3 i Figure 27. Contour map of bubble frequency f o r the plane % = 1.3 of run HG 1. N ' f r = 105 . d„ = 0 3 2 5 cm L oo Run HG I Bubbles Per Second ' , _ 1 Q 5 d„ = 0.325 cm F i g u r e 28. Contour map of bubble frequency f o r the plane X = 0 of run HG 1. F i g u r e 29. C o n t o u r 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 B = 1.3 o f r u n HG 2. r»-| , , , •- 1 , , , . 1 • ! • f--5 0 -4.0 -3.0 -'-!.0 -1.0 0.0 1.0 2.0 3.3 4.0 5.0 5.0 7.0 HORIZONTAL DtSTflNCt PflFMU.a TO N3Z7.LE IX CM. Figure 30. Contour map of bubble frequency f o r the plane X = 0 of run HG 2. Z - l . 3 Run HG 3 Bubbles Per Second Nrv =288 d 0 =0-325 cm 1 1 1 1 1 1 1 1 1 1 1— -3.0 -2.0 -1.0 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 H O R I Z O N T A L D I S T A N C E P A R A L L E L T O N O Z Z L E IN C M . Figure 31. Contour map of bubble frequency for the plane 3 = 1.3 of run HG 3. igure 33. Contour map of bubble frequency f o r the plane g = 1.3 of run HG 4. Figure 34. Contour map of bubble frequency f o r the plane X = 0 of run HG 4. 00 86 4.1.3 V e l o c i t y Measurements / As described 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 regions of the j e t . The i n t e n t was t h a t a v e l o c i t y map could be drawn and that t h i s i n f o r m a t i o n , combined w i t h the gas c o n c e n t r a t i o n and bubble frequency data measured e a r l i e r , would allow 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 expectations as t h e i r accuracy and r e p r o d u c e a b i l i t y were not considered t o be s a t i s f a c t o r y . 4.1.4 Measurements of Mercury Backflow into the Tuyere Mercury backflow was not detected i n the tuyere by the experimental method described e a r l i e r . 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 not detected allows the f o l l o w i n g p o s s i b i l i t i e s : 87 (i) When the t e s t e l e c t r o d e s were one n i c k e l wire and the tank w a l l , mercury splashed back i n t o the tuyere as a discontinuous phase. Thus the el e c t r o d e s were not coupled and there was no d e t e c t i o n . ( i i ) When the 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 penetrated the tuyere but d i d not contact both wires simultaneously. ( i i i ) Mercury penetrated the tuyere but f e l l short of c o n t a c t i n g e i t h e r of the n i c k e l w i r e s . (iv) Mercury d i d not flow back i n t o the tuyere; p o s s i b l y because the tuyere diameter was too small to al l o w s i g n i f i c a n t backflow, or p o s s i b l y because a s i t u a t i o n to encourage backflow d i d not 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 studied p r i m a r i l y as a backup to the air-mercury work. Many of the t e s t s done i n water were f o r the purpose of t e s t i n g e i t h e r techniques used i n t h i s work or techniques used by other i n v e s t i g a t o r s . To a c e r t a i n extent the air-water s t u d i e s served as a bridge between the air-mercury work reported here and previous work done by others, who u s u a l l y s t u d i e d the air-water or other photographable systems. In a d d i t i o n , . 88 advantage was taken 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 . high-speed cinematic photography) the water model was looked at to provide i n f o r m a t i o n which was e i t h e r unobtainable 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 through the mercury t e s t s . 4.2.1. Elapsed-Time Photography The technique of elapsed-time photography has been used by others, notably by Themelis et a l (74), to determine the envelope of a submerged a i r - j e t i n water. Tests were conducted on the photography of h o r i z o n t a l a i r j e t s i n water which show tha t one should be cautious 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 . Figure 35 i l l u s t r a t e s why. 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 both photographic 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 es the placement of the j e t envelope — whether i t w i l l correspond, say, t o 1 percent a i r or t o 10 percent a i r . The p i c t u r e s i n Figure 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 alone. Both p r i n t s are from the same negative — only the p r i n t i n g exposure was changed. S i m i l a r r e s u l t s could be shown f o r the case of d i f f e r e n t photographic c o n d i t i o n s but i d e n t i c a l p r i n t i n g c o n d i t i o n s . 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 not, 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 photograph of a submerged a i r j e t i n water. Two p i c t u r e s of t h e same photo-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 th e e x t e n t of p o s s i b l e v a r i a t i o n i n e n v e l o p e s i z e . 90 jets , expand or contract the envelope symmetrically. If one were to define the j e t tra 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 pictures of Figures 35 would d i f f e r considerably. In t h i s work the photographic conditions used for measurement purposes were always such as to obtain the maximum-size envelope that s t i l l maintained a dense, dark shade against a bright background. 4.2.2 Trajectory Determination by Probe and Photography A i r 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 in a manner similar to that used in the air-mercury system. In the water t e s t s , however, the data was obtained from a millivoltmeter placed across a known resistance i n the probe c i r c u i t . The m i l l i v o l t readings were normalized such that a reading of 100 i n -dicated that the probe as i n contact with water while a reading of 0 indicated that the probe t i p was completely surrounded by a i r . Although the m i l l i v o l t values cannot be assumed to d i r e c t l y represent volume percent l i q u i d phase they are however i n d i c a t i v e , i n that a lower reading 91 would correspond to a higher percentage of gas. 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 Figure 36. The t r a j e c t o r y of 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 of the j e t was taken and the t r a j e c t o r y was considered t o be the center of the envelope. 2. The data obtained from the e l e c t r o r e s i s t i v i t y probe (at more than 500 data p o i n t s per run) was evaluated and the t r a j e c t o r y was drawn through the p o i n t s of highest gas f r a c t i o n . The r e s u l t s from both of these methods i i are presented f o r runs a t N_ = 1500 and N „ = 6700 Fr Fr i n Figures 37 and 38. 4.2.3 Observations of J e t P u l s a t i o n The p u l s a t i n g behaviour of an a i r j e t i n water was observed by means of high-speed cinematic photography. Figure 39 i l l u s t r a t e s a t y p i c a l pulse 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 > 20 e .? 40 TD O CD <T 60 a3 £ i 80 > 100 -2 o -I 0 o o I Probe Position (cm.) gure 36. Probe t r a c e through an air-water j e t . 10 o Measured Envelope By Photography a Measured Trajectory By Probe 9 8 > £ o c a to 2 to b i N a c g to c <u E b 0 -2 Liquid Surface @ Z = l3lcm. j L _L L J L J I I L 0 6 8 10 12 14 16 18 Dimensional X-Distance (cm.) (Horizontal) 20 Figure 37. The envelope and trajectory of an air-water j e t as . determined by photography and probe. N / Fr = 1 5 0 0 . O Measured Envelope By Photography o Measured Trajectory By Probe Liquid Surface @ Z = I3 I cm. I l I I l I I l l I I I I I 1 I I I 1 I I I I I L 0 2 4 6 8 10 12 14 16 18 20 22 24 Dimensional X-Distance (cm.) (Horizontal) Figure 38. The envelope and t r a j e c t o r y of an air-water j e t as determined by photography and probe. - 6 7 0 0 . Fr t-O.OlOs. t=0.021s. Figure 39. A sequence of frames showing one complete p u l s a t i o n of an a i r j e t i n water. 9 6 - A submerged gas j e t i n a l i q u i d i s not a con t i n o u s , smoothly f l o w i n g stream but r a t h e r i s markedly 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 the 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 which then breaks up i n t o smaller bubbles. These events repeat themselves 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 aspects of j e t behaviour might be a n t i c i p a t e d from a knowledge of p u l s a t i o n frequency or amplitude. 4.2.4 Observations of Slugging Behaviour I t has been observed 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 j e t s t h a t there i s a"tendency f o r l a r g e bubbles or slugs t o r i s e prematurely of the main envelope of bubble F i g u r e 14 i s a s t i l l photo showing the l o c a t i o n of a s l u g o u t s i d e the j e t envelope, 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 of frames from a high-speed f i l m , the development of such a s l u g . The attempted measurement of gas f r a c t i o n l o s t t o slu g g i n g was u n s u c c e s s f u l . The catch-box technique could not be made t o work because the gas e n t r a i n e d i n the l i q u i d was c a r r i e d back out of the catch-box i n the l i q u i d stream (Figure 41). Various arrangements of s o l i d and/or wire screen b a f f l e s were f i t t e d to the catch-boxes i n an attempt to r e l e a s e the e n t r a i n e d gas. None was s u c c e s s f u l . t = 0.078s. t = 0.091s. F i g u r e 40. A sequence o f frames showing t h e development of a s l u g . 98 To flow meter j n Liquid entering with entrained gas |-— Catch - box Liquid leaving with entrained gas Figure 41. I l l u s t r a t i o n of the flow p a t t e r n i n the catch box. 99 CHAPTER 5 DISCUSSION 5.1 General 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 Since submerged gas j e t s i n l i q u i d metals have not p r e v i o u s l y been observed i n the d e t a i l o f f e r e d by t h i s study, a general d e s c r i p t i o n of an a i r j e t i n mercury w i l l be presented here. In i t s general f e a t u r e s , Run HG1 i s t y p i c a l of a l l j e t s s t u d i e d i n the air-mercury system, and various contour maps from t h i s run w i l l be r e f e r r e d to f o r purposes of i l l u s t r a t i o n . The h o r i z o n t a l contour maps of gas d i s t r i b u t i o n and bubble frequency, i l l u s t r a t e d f o r Run HGl i n Figures 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 the j e t c o n s i s t s of a core of high gas concentration and high bubble frequency which g r a d u a l l y decrease i n value toward the edge of the j e t . At the 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 yet i t i s not symmetrical, but apparently elongated i n a f o r e -and-aft d i r e c t i o n . 100 The v e r t i c a l contour map of 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 Figure 20 i s p a r t i c u l a r l y important as i t contains much of the new informat i o n which has been obtained i n t h i s study. The f i r s t aspect t o be noted i s th a t the j e t expands very r a p i d l y , immediately upon l e a v i n g the noz z l e . This i s an unexpected r e s u l t based on informa t i o n obtained from an examination of submerged j e t s i n the a i r -water system where i s i t c u r r e n t l y accepted t h a t an a i r j e t expands at a cone angle of about 20 degrees. In the a i r -mercury system i t would appear that the j e t expands at a much l a r g e r cone angle. Another important feature i s t h a t the j e t penetrates or expands behind the tuyere to a la r g e extent, again an occurrence t h a t one could not p r e d i c t by observing only the a i r - w a t e r system. In f a c t the j e t penetrates rearward to such an extent t h a t i t s t r a j e c t o r y , drawn through the poi n t s of maximum gas f r a c t i o n , appears to r i s e v e r t i c a l l y almost immediately upon l e a v i n g the tuyere. In a l l , the j e t looks very 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 expansion angle or cone angle of a i r j e t s blown i n t o mercury was measured under each of the 101 experimental c o n d i t i o n s . The width of the j e t was measured both from the contour maps and from independent probe measurements i n a transverse d i r e c t i o n , i . e . perpendicular to the d i r e c t i o n of i n i t i a l i n j e c t i o n i n t o the bath. In t h i s manner the n a t u r a l expansion of an a i r j e t i n mercury i s measured. These r e s u l t s , which are l i s t e d i n Table I I I , 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 than a i r j e t s i n water. The cone angle i s constant at roughly 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 modified Froude number or nozzle diameter. This value i s more than seven times greater than the 20° cone angle which was p r e v i o u s l y thought to apply t o a l l (subsonic) a i r j e t s r e g a r d l e s s of the medium i n t o which they were i n j e c t e d . I To check that the la r g e cone angle was not a f u n c t i o n of tank design and caused by p a r t i c u l a r s t i r r i n g p atterns i n the bath, the f o l l o w i n g t e s t was 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 the mercury was drained and f i l l e d w i t h water, and an a i r j e t was i n j e c t e d i n t o the bath and photographed by the elapsed-time technique described e a r l i e r . Such a photograph i s shown i n Figure 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 at the a n t i c i p a t e d 20° cone angle. The la r g e cone angles 102 Nozzle Cone* Run No. Diameter Angle (cm.) (Degrees) Fr HG 4 20.3 0.476 157.9 156.6 HG 2 20.3 0.325 142.9 146.1 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% Air; 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 during the air-mercury t e s t s . The cone angle 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 of the air-mercury system and not of the p a r t i c u l a r equipment geometry. The cone angle was a l s o measured as a f u n c t i o n of tuyere submergence, by v a r y i n g the depth of mercury i n the bath. Figures 43 and 44 show the gas c o n c e n t r a t i o n p r o f i l e s obtained at r e s p e c t i v e d i s t a n c e s of 0.3am. and 1.3 cm above the tuyere e x i t f o r operating c o n d i t i o n s corresponding t o those of Run HG 4. In each case, r e g a r d l e s s of tuyere submergence depth, the p r o f i l e s a r e i d e n t i c a l and, t h e r e f o r e , the cone angles are i d e n t i c a l and do not vary w i t h mercury depth over the range s t u d i e d . The range of submergence depths stud i e d produced a pressure change at the o r i f i c e of only 6 t o 7 percent. 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 the mercuro-s 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 the pressure of the system the cone angle 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 Figure 43. J e t width vs. tuyere submergence. Traverse taken at 0.3 cm. above the tuyere f o r Run HG 4. o Ui F i g u r e 44. J e t width vs. tuyere submergence. Traverse taken at 1.3 cm. above the tuyere f o r Run HG 4. § 107 5.3 J e t Diameter Although the cone angle may be used to deduce the j e t diameter near the tuyere, the j e t diameter i s s t i l l important as an independent parameter since the j e t does not expand at the o r i g i n a l cone angle over i t s e n t i r e t r a j e c t o r y length. Figure 45 describes the r e l a t i o n s h i p between j e t diameter and t r a j e c t o r y length determined both by experiment i n the air-mercury 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 accepted cone angle of 20°. Values of the j e t diameter i n the three experimental curves were obtained from the 1 percent a i r contours of the various h o r i z o n t a l planes. The diameter was measured i n the transverse d i r e c t i o n s i n c e , as i n the cone angle measurements, i t was thought t h a t t h i s would best r e f l e c t the n a t u r a l expansion of the j e t . I t can be seen t h a t i n i t i a l l y the j e t s expand q u i c k l y and then tend to approach a constant diameter and r i s e as a column. I t appears t h a t the j e t diameter increases both w i t h i n c r e a s i n g Froude number and o r i f i c e diameter and i s , i n the a i r -mercury system, very much greater than t h a t p r e d i c t e d by models of continous expansion at a cone angle of 20°. 2 3 4 5 6 7 8 9 Distance Along Jet Trajectory , s , (cm) Figure 45. J e t diameter vs. distance along t r a j e c t o r y , o 00 109 5.4 J e t T r a j e c t o r y I t was seen e a r l i e r i n Figure 20 and i n s i m i l a r contour maps (Figures 22, 24, and 26) t h a t the 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 immediately a f t e r the j e t e x i t s the tuyere. Figures 46 t o 49 compare, f o r each run, the t r a j e c t o r y experimentally determined by measurements i n the air-mercury system to those which would be p r e d i c t e d by the model of Themelis e t a l (74) using both the p r e v i o u s l y accepted cone angle of 20° and the experimentally measured cone angle i n each case. I t i s obvious t h a t the model of Themelis et a l , when used wi t h a 20° cone angle, 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, overestimating the h o r i z o n t a l p e n e t r a t i o n by up to 1500 percent i n Run HG 3. When the experimentally determined cone angle 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 to underestimate the h o r i z o n t a l p e n e t r a t i o n by a small amount. lOr T 1 1 1 1 1 1 1 T r N'Fr = 105 d 0 = 0.325 cm •- Themelis et ol :— experimental l l l 1 8c 20 155 155 ' 6C = 5° 2 3 4 5 6 7 8 9 10 II Horizontal Distance From Nozzle (cm) 12 1-1 F i g u r e 46. Comparison of experimental and t h e o r e t i c a l j e t g t r a j e c t o r i e s f o r Run HG 1. - I O I — 9 — 1 8" S 7 ' -2 6 ! -4 1-r i. / J L T 1 r = 0 . 3 2 5 cm Themelis et al experimental J L JL. T r 8C = 20° • 8C -- 145 ° 8C = 145 °" l l 0 1 2 3 4 5 6 7 8 9 Horizontal Distance From Nozzle (cm) 10 II 12 Figure 47. 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 2. 10 9 8 7 6 5 4 3 2 I 0 -I i r 1 r V T 1 1 r d„ =0.325 cm _1_ y Themelis et ol _1_ _ l_ • experimentol J i I 6. = 20 ° Gc = 155° 9C = 155° I 2 3 4 5 6 7 8 9 10 II Horizontal Distance From Nozzle (cm) 12 F i g u r e 48. 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 3. i—1 lOr e 8 o a < _L_ 0 T 1 1 — r / T 1 1 1 1 " T T-N'Fr =20.3 d„ = 0.476 cm • - Themelis et ol 9C =20 " -j II ti II — experimentol 9e -- 157 ° 8C « I57» _1 I L 1 2 3 4 5 6 7 8 9 Horizontal Distance From Nozzle (cm) 10 II 12 Figure 49. Comparison of experimental and theoretical j e t t r a j e c t o r i e s for Run HG 4. 114 5.5 J e t P e n e t r a t i o n 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 the outer boundaries or envelope of the j e t have been measured i n the air-mercury system and are presented i n Table IV. Before proceeding w i t h the d i s c u s s i o n , the terms used i n the t a b l e should 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 c o - o r d i n a t e 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, the h o r i z o n t a l plane l o c a t e d 6 .3 cm. above the tuyere. S i m i l a r l y , the forward p e n e t r a t i o n i s the 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 the tuyere at which the l e a d i n g edge of the j e t envelope i n t e r s e c t s the plane a = 6 . 3 , w h i l e the back p e n e t r a t i o n i s the h o r i z o n t a l d i s t a n c e from the tuyere at which the r e a r edge of the j e t envelope i n t e r s e c t s the B = 6 .3 plane. I f the i n t e r -s e c t i o n p o i n t l i e s ahead of the n o z z l e , the 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 the n o z z l e , the p e n e t r a t i o n value i s negative. Thus, the back-penetration values i n Table IV show t h a t the j e t envelope extended behind the n o z z l e a s i g n i f i c a n t d i s t a n c e i n every case. The 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 or tuyere Maximum Maximum Run No. N i Fr Nozzle Diameter (cm. ) Tr a j e c t o r y P e n e t r a t i o n ( cm. ) Forward Penetration (cm. ) Back Penetr; (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 value of each p a i r i s obtained from the contour: 1% A i r ; The second value i s from the contour: 1 Bubble Per Second. TABLE IV: 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 of the j e t envelope appears to increase w i t h Froude number and p o s s i b l y w i t h tuyere diameter as w e l l but no c l e a r trend i s i n d i c a t e d f o r the pen e t r a t i o n of the rear of the envelope. Table V compares the pe 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 the model of Themelis et a l ( 7 4 ) . I t can be seen t h a t w i t h the cone angle of 2 0 ° , the model g r e a t l y overestimates 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 the previous s e c t i o n . Although the maximum forward p e n e t r a t i o n i s roughly p r e d i c t e d , the model i n d i c a t e s the re a r of the envelope to l i e about as f a r i n f r o n t of the tuyere as i t i n f a c t penetrates behind i t . That the model f a i l s to p r e d i c t the pen e t r a t i o n of the j e t behind the tuyere e x i t i s an important c o n s i d e r a t i o n when appl y i n g i t t o processes such as copper converting where the tuyeres are mounted f l u s h w i t h the i n s i d e w a l l of the v e s s e l . When the experimentally-determined cone angles are used, the model adequately r e f l e c t s the a c t u a l 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 . This i s because the Themelis model assumes the j e t to expand as a f u n c t i o n of i t s h o r i z o n t a l Run No. CONE* NOZZLE TRAJECTORY MAXIMUM* MAXIMUM* ANGLE N' DIAMETER PENETRATION FORWARD BACK (degrees) h r (cm.) (cm.) . PENETRATION PENETRATION (cm.) (cm.) HG4 experimental 157 20.3 0.476 0.5 5.5 -3.4 theore t i ca l 157 H II 0.1 0.6 -0.5 theore t i ca l 20 n II 4.0 4.9 +3.1 HG2 experimental 145 20.3 0.325 0.5 4.3 -2.8 theore t i ca l 145 II II 0.1 0.7 -0.4 theore t i ca l 20 II II 2.9 3.6 +2.3 HG1 experimental 155 105 0.325 0.5 6.4 -3.5 theore t i ca l 155 II II 0.3 1.5 -1.0 theore t i ca l 20 n H 5.2 6.3 +4.1 HG3 experimental 155 288 0.325 0.5 7.0 -2.6 theore t i ca l 155 n n 0.5 2.9 -1.9 theore t i ca l 20 n II 7.2 10.1 +4.3 * The experimental ' values are an average of those obtained from both the 1% a i r and 1 Bubble per Second contours. TA8LE V: 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 the c o r r e c t cone angles are i n s e r t e d , the t r a j e c t o r y penetrates only a very short d i s t a n c e . I s h i b a s h i (83) has developed the f o l l o w i n g expression f o r back-penetration of an a i r - j e t i n water: - a 5 " = 1'6 ( N F r \ where 1 = pe n e t r a t i o n d i s t a n c e behind the nozzle do = nozzle diameter N' = modified Froude number r r Lo = nozzle submergence depth That the r e l a t i o n s h i p was developed from work i n the a i r -water system i n d i c a t e s that the back-penetration r e f e r r e d to by I s h i b a s h i may w e l l be th a t due to slug formation. When a p p l i e d to the air-mercury system, equation 5.1 g r e a t l y underestimates the degree of measured back-p e n e t r a t i o n . . (5.1) 119 5.6 O r i g i n s of J e t Behaviour 5.6.1 J e t P u l s a t i o n s There i s thought to be a strong p o s s i b i l i t y t h a t the key to understanding the behaviour of g a s - l i q u i d j e t s l i e s i n the study of t h e i r p u l s a t i n g nature. High-speed photographs of a i r j e t s i n water, s i m i l a r t o the sequence i n Figure 39, sometimes show a complete break i n the a i r stream i s s u i n g from the nozzle. Were high-speed photographs p o s s i b l e i n the mercury bath they might have i l l u s t r a t e d a complete flow 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 tuyere between p o s i t i v e forward p u l s a t i o n s . The experiments designed to detect such a backflow i n t o the tuyere were unsu c c e s s f u l , but the ex i s t e n c e of t h i s behaviour cannot be r u l e d out. A p e r i o d i c rearward motion of l i q u i d would e x p l a i n why the j e t envelope extended so f a r behind the tuyere — i n a d d i t i o n t o s l u g - l i k e bubbles which r i s e v e r t i c a l l y , gas bubbles could be d e f l e c t e d rearward by l i q u i d 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 L i q u i d Although 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 of the ambient f l u i d medium have no e f f e c t upon the expansion behaviour of the j e t , i t i s obvious when comparing the observations of an a i r j e t i n water to 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 important i n t h i s regard i s s t i l l not c l e a r . Table VI shows d e n s i t y and surface 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 the greatest value d i f f e r e n c e between mercury and water. The d e n s i t y of mercury i s about fourteen times that of water wh i l e the surface t e n s i o n of mercury i s greater by approximately a f a c t o r of seven. E i t h e r or both of these p r o p e r t i e s could have been res p o n s i b l e f o r the seven-fold increase i n cone angle experienced i n the air-mercury system,.although the d e n s i t y has to be the favoured candidate because of i t s greater range. Spesivtsev e t a l (73) have s t u d i e d the 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 i n d i c a t e t h a t the l i q u i d d e n s i t y i s the f a c t o r which determines the p e n e t r a t i o n d i s t a n c e of 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 surface t e n s i o n has some i n f l u e n c e , i t i s small i n comparison to 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 Systems. 5.7.1 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 Since i t i s not c e r t a i n which of the p h y s i c a l p r o p e r t i e s play the dominant r o l e i n d i c t a t i n g the 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 at t h i s time to e x t r a p o l a t e the r e s u l t s of t h i s work to m e t a l l u r g i c a l systems of i n d u s t r i a l s i g n i f i c a n c e . Table VI, however, shows the d e n s i t i e s of l i q u i d copper and l i q u i d i r o n t o l i e roughly midway between those of water and mercury, and i f the l i q u i d d e n s i t y i s the determining f a c t o r i n j e t behaviour one might expect the j e t i n a copper converter or i n a steelmaking converter to expand at r a t e between t h a t of an a i r j e t i n water and that 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 processes comprise non-isothermal, r e a c t i v e systems. The sudden expansion of a c o l d gas j e t upon contact with a hot metal bath or a s i m i l a r expansion due to an exothermic r e a c t i o n w i l l cause the j e t to expand and r i s e more r a p i d l y than a n t i c i p a t e d . I t i s probable then t h a t an a i r j e t i n mercury r e f l e c t s f a r more a c c u r a t e l y the behaviour of a gas j e t i n a copper converting or steelmaking process.than does an a i r j e t i n water. AIR (20 C) WATER (20 C) MERCURY (20°C) LIQUID COPPER LIQUID IRON DENSITY, P (gm./cm3) 1.2 x 10 -3 1.0 13.6 7.7 7.1 SURFACE TENSION, a' (dynes/cm) undefined 73.5 465 800-1300 800-1300 VISCOSITY, V (cp) 1.8 x 10 -2 1.0 1.6 2.5- 3.5 5.2- 7.0 KINEMATIC VISCOSITY v=y/p (cm2/sec) 15.2 1.0 0.1 0.3-0.5 0.7-1.0 TABLE VI COMPARATIVE PHYSICAL PROPERTIES OF AIR, WATER, MFJ3CURY, LIQUID COPPER, AND LIQUID IRON OR STEEL. 123 5,. 7. 2 . Phenomenological Comparison Although, as mentioned e a r l i e r , i t i s not 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 r e s u l t s of t h i s work to the more complicated i n d u s t r i a l 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 ideas presented i n t h i s t h e s i s . 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 de-s u l p h u r i z a t i o h of s t e e l (86) and both tuyere e r o s i o n and back-wall e r o s i o n during copper c o n v e r t i n g (87) w i l l be considered. 5.7.2.1 Lance plugging i n the 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 Since e a r l y 1973 the S t e e l Company of Canada, L i m i t e d , has been d e s u l p h u r i z i n g small tonnages of b l a s t furnace i r o n i n torpedo l a d l e s by means of the pneumatic i n j e c t i o n of powdered magnesium impregnated coke or 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 lance d i r e c t e d downward at an angle of 30° t o the v e r t i c a l (86). At one stage i n the development of t h i s procedure lance plugging was a s e r i o u s problem. The photograph of 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 blockages o c c u r r i n g at the nose of the lance. The d e p o s i t w i t h i n the lance was determined to be p r i m a r i l y hot metal 124 F i g u r e 50. Photograph 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 b a c k f l o w of l i q u i d s t e e l i n t o a l a n c e . C o u r t e s y o f Wood e t a l (86) . 125 which had been drawn back up the lance pipe by v i r t u e of g a s - l i n e pressure f l u c t u a t i o n s which occurred during i n j e c t i o n . That hot metal 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 lance i l l u s t r a t e s not only the existence of back-penetration but a l s o the magnitude of 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 . Although not s u c c e s s f u l l y measured i n l a b o r a t o r y 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 backflow does occur i n the tuyere and a strong case i s made f o r the importance of studying the p u l s a t i n g nature of submerged gas j e t s i n l i q u i d s . 5.7.2.2. Tuyere Erosion During Copper Converting S i m i l a r evidence supporting the backflow of l i q u i d i n t o the tuyere i s provided by the severe tuyere d e t e r i o r a t i o n experienced i n copper converting (87) . The r e s u l t i n g c o n f i g u r a t i o n of the nose of the tuyere suggests t h a t r e a c t i o n was t a k i n g place very c l o s e t o the t i p of the nozzle or w i t h i n the tuyere 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 backflow. 126 5.7.2.3 Back-Wall Erosion In A Copper Converter Some of the most severe e r o s i o n problems i n a copper converter occur on the back w a l l of the v e s s e l , immediately above and behind the tuyeres. In the past t h i s occurrence has not been s a t i s f a c t o r i l y explained. However, i f . the f i n d i n g s of the present air-mercury s t u d i e s are extended t o the l i q u i d copper system one of the 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 the j e t r i s e s very q u i c k l y and penetrates rearward to a l a r g e extent and a l s o because the tuyeres of a copper converter are i n s t a l l e d f l u s h w i t h the i n s i d e w a l l of the v e s s e l , the j e t impinges d i r e c t l y upon the w a l l of the converter i n the reg i o n corresponding to tha t of gr e a t e s t e r o s i o n . When, i n a d d i t i o n , i t i s remembered th a t the tuyere i t s e l f i s being eroded away by r e a c t i o n w i t h i n the nozzle and i s receding i n t o the converter w a l l , i t can be a n t i c i p a t e d t h a t the e r o s i o n of the converter w a l l would be as extensive as i s i n f a c t seen to be the case. Since t h i s w a l l e r o s i o n has not been w e l l - e x p l a i n e d p r e v i o u s l y , the c o r r e l a t i o n developed i n the above argument provides remarkably 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 converter behave s i m i l a r l y to those of the air-mercury system i n t h a t they r i s e very q u i c k l y and penetrate behind the plane of the nozzle 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 of gas volume f r a c t i o n and bubble 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 operating c o n d i t i o n s covering a range of modified Froude numbers between 20 and 300 and nozzle diameters of 0.325 cm. and 0.47 6 cm. ( i i ) The cone angle of an a i r j e t i n mercury was found to be approximately 150° and was not seen t o vary s i g n i f i c a n t l y w i t h e i t h e r modified Froude number or nozzle diameter. This value i s roughly 7 times t h a t measured f o r an a i r j e t i n water. ( i i i ) . As a consequence of the above, the 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 of b o t h , i t s t r a j e c t o r y and forward 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 not continue to expand at the o r i g i n a l cone angle, but r i s e s as a column through most of i t s v e r t i c a l ascent. 128 (v) Although 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 of the ambient f l u i d medium have no e f f e c t upon the expansion behaviour of the j e t , the r e s u l t s of t h i s work c l e a r l y show t h a t the 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, the cone angle. I t i s suggested that the f l u i d d e n s i t y has the dominant i n f l u e n c e i n t h i s regard. (vi) I t i s probable t h a t i n d u s t r i a l copper convert-ing and steelmaking s i t u a t i o n s are more c l o s e l y represented by the air-mercury system then by the air-wa t e r system. However, the non-isothermal, r e a c t i v e nature of the i n d u s t r i a l operations r e q u i r e s a cautious 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 experimental systems. 6.2 Suggested Future Work (i) I t i s recommended th a t non-isothermal experiments be pursued i n p o s s i b l y the argon-lead or argon-aluminum systems to determine the e f f e c t of sudden gas expansion due to heating upon the cone angle of the j e t . ( i i ) U t i l i z i n g the a i r - w a t e r system, the pressure f l u c t u a t i o n s i n the a i r - l i n e near the tuyere should be measured and r e l a t e d t o the p u l s a t i o n s observed by high-speed photography. 129 ( i i i ) S i m i l a r l y , the pressure p u l s a t i o n s of an a i r j e t i n mercury and those of a non-isothermal g a s - l i q u i d metal system should be monitored and r e l a t e d to operating c o n d i t i o n s and to phenomena o c c u r r i n g w i t h i n the bath, keeping i n mind the p o s s i b i l i t y of d e v i s i n g a s u i t a b l e monitoring system f o r i n d u s t r i a l process c o n t r o l . (iv) In general, work i s necessary 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 behaviour held by the d e n s i t y , v i s c o s i t y and surface t e n s i o n of the l i q u i d . APPENDIX I CIRCUIT DIAGRAMS C i r c u i t diagrams of the e l e c t r o n i apparatus used i n conjunction w i t h the e l e c t r o r e s i s t i v i t y probe during the a i r mercury experiments. 131 Figure 51. C i r c u i t diagram of the i n t e g r a t o r used i n the air-mercury experiments t o measure gas volume f r a c t i o n . 132 166 C12 117 V AC. +5V, D.C: IK/L I K A -AVWv—r—x pl|i2|N(io1[9lfe f - ^ W W -M600 22 K A @ 2N4I26 77?T7T 3^ Figure 52. C i r c u i t diagram of the bounceless switch and power supply used i n the air-mercury experiments. APPENDIX I I CONTOUR PROGRAM Fol l o w i n g i s an example of the computer program used to produce the contour maps of gas volume f r a c t i o n and bubble frequency. CNT0UR i s a sub-program a v a i l a b l e i n the UBC computing centre l i b r a r y which allows an i r r e g u l a r g r i d of value p o i n t s to, be represented as a two-dimensional contour map. c PRCCRAC TC CCNTCUF XY PLANES FCC FUN FG 2 1. 003 0001 DIMENSICN X P l l l ) , 1 F U 5 ) , Z F I U . 1 9 ) , T ITLE I20 ) 2.000 0002 CALL FLCTS 3.000 c SET LP >F £ YF ARRAYS 4. 000 . 0 L 0 3 " " 99 READl 5, IOC) MOFDAT 5.000 CCC4 100 F C F N A T U 1 ) . 6. COO 0C05 I F ( y C R C A T . E C . l ) GC TC 3C4 7. COO 0006 READ I5 .2C5) ( T I T L E ( I ) 1 1 - 1 , 2 C ) 8.000 CCC7 305 FCFMA7(20A4) 9. OOO GC08 XPI1) = C . £ 1C.000 0109 CC 101 1=2, 11 .11.000 CC10 XP ( I )=>F (1 -11+1 .0 12.003 0011 101 CONTINLE 13.000 0012 Y P ( 1 ) = 1.3 14.000 CC13 DC 1C2 1=2,8 15.00C 0014 YP( I ) = YPI I-11 + C.5 16.000 0015 102 CCNTINLE 17.000 0016 YP (5 )=YF (8 )+0 .2 18.000 0017 YP( 10 ) = YP( 9 ) fC J .2 19.000 0G18 CC 1C3 1=11,19 2C. COO 0C19 YP ( I>=YF( I -11+C.5 21 .000 C020 103 CONTINUE 22.000 C FLCT .The AXES 23. COO 0021. CALL A X I S I C . C C . C M - C R I Z C N K L CISTANCE PARALLEL TC NCZZLE IN C M . ' , 24 .000 1 - 4 5 , 1 2 . 0 , 0 . 6 , - 5 . 0 , 1.0) 25 .000 0022 CALL A X I S I C . O . C . O , ' F C R I Z C N T A L CISTANCE PERPENDICULAR TO NOZZLE IM 26.000 1CM. • , + 49 , 1 C . C, C.C. C , - 5 . 0 , 1 . C I 27.000 0023 CALL SYKECL (0 .5 , 9 .5 ,0 .14 ,T ITL E , C . , EO ) 28.000 c READ IN Th 2 DATA 29. 000 0024 DC 2C1 1=1,11 3C.000 C025 F E i C ( 5 , 2 ) < Z F ( I , J ) , J=l, 19) 31. 000 0026 2 FQRNAT<4X,19F4.C> ' 22.0CO 0027 201 CCNT I M F 33.000 C FLCT THE CCMCURS ' 34. 000 0028 DC 2C2 1=1,11 25.0CC 0029 I F I I . E C . 1 1 1 G 0 TO 2 C 1 36 .000 0C30 C N = F L C A T ( I ) * 1 0 . 0 37.COO 0031 GO TO 2C2 38.000 0032 301 CCNTINUE 39.000 0033 CN=1.C 4C. 000 0024 202 CONTINLE 41.000 0035 CALL C N T C U F ( X P , 1 1 , Y P , 1 9 , Z P , 1 1 , C N , 3 . 0 , C N ) 42 .000 CC36 3 0 3 _ CCNTINLE 43.CCO 0037 CALL P L C T l 1 4 . C 0.C , -2 ) 44.000 CC36 GC TC 99 45. 000 0C39 204 CCNTINLE 46.CCO 0040 CALL FLCTND 47 .000 0041 STCP 48. COO 0042 EN'D 49 .000 *CPT IONS IN" EFFECT* IC, E6CC IC , SCUR CE ,.NOL I S T , NGOECK ,LCAD .NCMAP *OPTICNS 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 • STAT I ST ICS * N'C C IAGNC ST ICS G~EN E~RAT tO NC ERRORS IM f-'AIN NC STATEMENTS FL A G G E C IN T t- E A B C V E CCMt> IL AT I CN 5 EXECLTI CN T E R M NATEC APPENDIX I I I . GAS DISTRIBUTION CONTOUR MAPS. A complete set of contour maps d e p i c t i n g the volumetric gas d i s t r i b u t i o n w i t h i n the j e t of run HG 1 i s included i n t h i s appendix. Each contoured plane i s l a b e l l e d according to the nomenclature described i n Figure 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 T —I 1 i " I— "I 1 1 -2 0 -1.0 0.0 1.0 2.0 3.0 4.0 5.0 H O R I Z O N T A L D I S T A N C E P A R A L L E L T O N O Z Z L E I N C M . 6.0 7.0 8.0 'Jo. JO! s n i v . / i i . No. -:C! 10 O I V . / l N . x=-o.2: UJ _ l o o z o UJ o z cc I— Qra" ( X o ceo UJ_;--4.0 -3.0 —I -2.0 , : T 1 r — 1 1 1 I 1.0 0.0 i.O 2.0 3.0 4.0 5.0 H O R I Z O N T A L D I S T A N C E P A R A L L E L T O N O Z Z L E I N C M . 6..0 ~I 7.0 S.O No ai'.l ISDiV/lU. CD : x=-o.i j _ i i 1—: 1 1 -4-v _ n Run HG I Volume % Air N'Fr =105 d 0 = 0.325 cm - 4 . 0 -3.0 1 - 2 . 0 T T 1 1 1 1 1 r— .1 0 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 ' H O R I Z O N T A L D I S T A N C E P A R A L L E L T O N O Z Z L E I N C M . a.o X=0-.2 h-1 N<>. 40i in i ) i v AN. X=l .0 Sim" UJ o o CCc: UJ o •—.a Onl" cr C C O uJ_;-~t 1 1 1 1 1 1 r — -4.0 -3.0 -2.0 -J.0 0.0 1.0 2.0 3.0 4.0 5.0 H O R I Z O N T A L D I S T A N C E P A R A L L E L T O N O Z Z L E I N C M . —1— e.o 7.0 —1 : e.o Mo .-.01 U S I V C / I M . SfrT !. X=2.0 ;o Di v A M : Z = - 0 . 7 J i ' r v i " rvi o Ql-CC _) CJ Q cc UJ »— CO a j o <XfM. r — I z o rvi •—» a : O o " iTi ' - ' i 'IT'!": i i : i i 1 \ 1 1 1— -4.0 -3.0 -2.0 -1.0 0.0 t.O 2.0 3.0 4.0 5.0 H O R I Z O N T A L D I S T A N C E P A R A L L E L T O N O Z Z L E I N C M . e.o 7.0 8.0 Z---0.2 CO CH-.WT 01 frST CJ UJo (VI O ST _ J o a £ c cr UJ a. i -r — CO - J ° . CXfM. o rvi • •—• O o X . ^ /(.V.. i Z = 0 . 3 . - 1 , -4.0 -3.0 -2.0 -i 1 1 : 1 : 1 1 ' _ i n nn 1 0 2.0 3.0 4.0 5.0 H O R I Z O N T A L D I S T A N C E P A R A L L E L T O N O Z Z L E I N C M . i — 5.0 r -7.0 i 8.0 cnA[7r NO. o: .1 AST C H A R T N O CI o 091 T9T Z9T 6 o e9T z *9T S9I 991 Z.9T 89 [ 169 CUT : TZ LJr> O T. cn — cn _ i ZD <_> o z a or 0_ : I— iV> i *—» a !_ja . CCoi t— . zr O rvj . . -"-an i " r=e.s r ( I • : I ' • | : -2 .0 . -1.0 0.0 —I • 1 ' — l 1 1 1 i n 2.0 3 0 4.0 5.0 6.0 V E R T I C A L D I S T A N C E F R O M N O Z Z L E I N C M . - i — 7.0 —1 -8.0 APPENDIX IV BUBBLE FREQUENCY DISTRIBUTION CONTOUR MAPS A complete set of contour maps d e p i c t i n g the bubble frequency d i s t r i b u t i o n w i t h i n the j e t of run HG 1 i s included i n t h i s appendix. Each contoured plane i s l a b e l l e d according t o the nomenclature described i n Figure 18. X=-3.5 N'T :('•! !C - t i i V . / ;N o 0~ X=--3.0 .o CJ rvi o UJ cr i — • c r CJ CCO UJ _•-.—! , — 3.0 4.0 T O N O Z Z L E I N -1— 5.0 I— 6.0 — 1 — 7.0 -1 8.0 -4.0 -3.0 -2.0 -1.0 0.0 H O R I Z O N T A L 1 1 D I S T A N C E P A R A L L E L C M . X=-2.5 O o U J (X cn cr o i C C O ; C i J J -_| P j , , 1 1 1 1 1 1 1— -4 0 -3 0 -2.0 -1.0 0.0 1.0 2.0 3.0 4.0 5.0 6.0 H O R I Z O N T A L D I S T A N C E P A R A L L E L T O N O Z Z L E I N C M . 7.0 S.O tn No. /101 »0PIV . / lN H O R I Z O N T A L D I S T A N C E P A R A L L E L T O N O Z Z L E I N C M . N o *'» l ' ; D i ' . ' / i N X=r0.5; " M — — ; 1 1 • 1 T 1 : r — i 1 ' 1 — — 1 1 1 -4.0 -3.0 -2.0 -1.0 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 HORIZONTAL DISTANCE PARALLEL TO NOZZLE IN CM. -I ; , .... •.,! . . . . . i . .... : . , I • ; i I ; • ?H 1 1 1 1 1 1 : 1 1 1 1 1 r— 1 -4.0 -3.0 -2.0 -1.0 0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0-HORIZONTAL DISTANCE PARALLEL TO NOZZLE IN CM. Mo. 401 10DIV. / IN N o . ACl iO Dt V. / i N . f„v> /.(•; ; 0 O ; V / i N . X=2.0 .o xiid" O UJ cr Qi>i" cr o 00 T 1 1 1 I 1 1.0 0.0 1.0 2.0 3.0 4.0 HORIZONTAL DISTANCE PARALLEL TO NOZZLE IN CM. - 1 — 6.0 -1 7.0 4.0 -3.0 -2.0 5.0 8.0 No. - i l l 10 D I V / l N O i V / i N <_> UJo rvi' o ce-cz _ i r> t_) a z = » uJ c _ a. cc UJ o_ CJC Z->-a _i= CEfM. r — 1 z o rvi • cc 1—1 -4.0 -3.0 -2.0 1 : 1 2 q 1'0H0RIZ0NTflL DISTANCE PARALLEL TO NOZZLE IN CH. T 3.0 T 4.0 5.0 ~I— 6.0 —I 1.0 B.O 193 UJo rvi O cc-(X —1 ' 3 CJ a z ° :£= UJ o_ cf • I— ; <^  a CEoi : »—i ' cc : Rum HG I Bubbles Per Second N'p, =105 ' F r d 0 = 0.325 cm N o . DIV / I N . 6 . 0 10 L)l V/itsl. 861 Z=6.3 -LLtLliilii; T: c_> : UJo rvi O cr C J o z = w° r — ico : t—t ;0 l - J 0 . i z rvi r r O o I '2.5 • i . i i 1 1 1 • 1 1—: r — ' 1— -5.0 - ! . 0 0.0 1.0 2.0 3.0 4.0 5.0 6.0 VERTICAL DISTANCE FROM NOZZLE IN CM. - | — 7.0 to o o S.G N O . O l TO?! zoz £0Z 204 SOZ r H O R I Z O N T A L DISTANCE PERPENDICULRR TO NOZZLE IN Crl' • j -5 0 -4.0 -3.0 -2.0 -1.0 0.0 !.0 2.0 3.0 4.0 5. I I I I I J- 1 1 : 1 -1 > 1 i 90Z LOZ 2.0 -3.0 T 0.0 "I VERTICai T 1 1 r 2.0 3.0 4.0 5.0 DISTANCE FROM NOZZLE IN CM. r o.o T 7.0 8.0 to O CO 60Z 210 REFERENCES (1) Themelis, 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 . Metals , 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 Smelting i n the Noranda Process", Paper Presented at the 104th AIME annual meeting, New York C i t y , N.Y., February 16-20, 1975. (3) B r a n t l e y , F.E. and Schack, C.H., U.S. Bureau of Mines Rep. Invest. 6113, 12 pp. (4) Oudiz, J . J . , J . Metals, V o l . 25, No. 12, 1973, pp. 35-38. (5) Henderson, J.M. et a l , U.S. Pat. 3,623,863, 1971. (6) McKerrow, G.C. and P a n n e l l , D.G., Can. Met. Quart., Vol.. 11, No. 4, 1972, pp. 629-633. (7) Komlev, G..A. 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