LAUSR

Abstract A new mathematical model of bubble Sauter mean diameter (d32) in the fine bubble-dominated columns (FBCs) is developed. Unlike previously proposed models suggesting a linear relationship existed between d32 and the diameter of the maximum stable bubble (dmax), the combined effects of dmax and the diameter of the minimum bubble (dmin) on d32 were considered in the new model. Accordingly, the effects of physical properties of four liquids (e.g., distillated water, 10 wt% aqueous ethanol, 0.1 wt% aqueous carboxymethyl cellulose (CMC) and 10 wt% aqueous sucrose) and energy dissipation rate on bubble size distribution (BSD) and d32 were discussed by introducing the models of dmax and dmin. Theoretical calculations were compared with the experimental results from the air–water system in the fine bubble-dominated column under different operation conditions. It is shown that satisfactory predictions of d32 can be achieved with the new model and the relative errors are less than 9%.