PREDICTION OF THE BUBBLE-SIZE GENERATED BY A PLUNGING LIQUID JET BUBBLE COLUMN

In this paper a model is presented to predict the maximum bubble size generated within the mixing zone at the top of a plunging liquid jet bubble column. The model uses a critical Weber number, where the energy dissipation rate per unit volume is derived from the theory of liquid-jet gas ejectors. The length of the mixing zone, and hence its volume, was determined experimentally from the vertical axial pressure profile along the wall of the column. Thc model was tested experimentally for a range of column and jet diameters, jet velocities, and liquid physical properties, and it was found that the measured maximum bubble diameter was in good agreement with the model predictions based on a critical Weber number of 1.2. It was also found that the bubble diameter distribution was fitted by a log-normal distribution, with a Sauter-mean-to-maximum-diameter ratio of 0.61 which is consistent with reported literature values.