HYDRODYNAMICS OF A PLUNGING LIQUID JET BUBBLE-COLUMN

In this study the flow characteristics in the pipe-flow zone of a plun ging liquid jet bubble column are investigated. The effect of column d iameter, and gas and liquid flow rates on the bubble size and gas void fraction for the bubbly and churn-turbulent flow regimes are determin ed experimentally for an air-water system. Applying drift-flux analysi s to the flow, it was found that in the bubbly flow regime the distrib ution coefficient was approximately equal to 2 at a liquid Reynolds nu mber of 1500, decreasing to approximately unity for a liquid Reynolds number above 10 000. A similar trend was observed for the churn-turbul ent flow regime, with distribution coefficient values in the range 1.1 0 to 0.91 over a similar range of liquid Reynolds numbers. It was also found that the bubble size remained constant in the bubbly flow regim e. In the churn-turbulent flow regime, however, an increase in bubble size was observed due to coalescence.