UBC Theses and Dissertations
Boiling heat transfer during cooling of a hot moving steel plate by multiple top jets Franco, Geoffrey
Experiments have been carried out on a pilot scale run-out table to study heat transfer during cooling of hot moving steel plates. Two lines of top water jets, each holding three nozzles are used in the study. Emphasis has been placed on studying the effect of nozzle stagger, jet line spacing and plate speed on the overall heat extraction rate. Tests are performed for 3 nozzle stagger arrangements (no-, half- and full-stagger) jet line spacings (25.4 cm, and 50.8 cm) and 2 plate speeds (0.35 m/s and 1.0 mIs) Results show that similar heat extraction rates are obtained regardless of nozzle stagger, for as long as the distance between nozzles and jet lines are held the same. However, cooling is more uniform when the nozzles are fully-staggered. No significant pooling occurred in between jet lines to affect cooling efficiency of the second jet line. More efficient heat extraction is attained when using closer-spaced jet lines and slower plate speeds. The heat extraction capability of an individual nozzle is generally determined by the surface temperature of the to-be-impinged and surrounding areas of the steel plate to be cooled. Nozzle arrangements of subsequent jet lines with respect to hot and cold regions developed by prior jet line impingement is crucial in maintaining uniform and efficient cooling of the hot plate or strip.
Item Citations and Data
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