Size distribution of bubbles in agitated viscous <scp>N</scp>ewtonian and non‐<scp>N</scp>ewtonian solutions

Abstract

Abstract The effects of impeller type, Newtonian shear thinning liquid viscosities, and noncoalescing conditions on the impeller gas cavities, impeller power consumption, and Sauter mean bubble diameter ( d 32 ) in a multiphase agitated vessel were systematically studied. An underwater recording technique was used to study gas cavities and bubble size in various operating and design conditions. The gas cavity images were used to relate d 32 to gas cavity structure. It was observed that d 32 values increase with an increase in Newtonian and shear thinning liquid viscosities. Results also indicate that impellers operating in shear thinning liquids consume higher gassed power at the same operating conditions compared with those in Newtonian fluids. In addition, the d 32 values in noncoalescing liquids are substantially smaller compared with those in coalescing solutions at the same P g / V . Mathematical correlations are proposed for estimating the d 32 in the impeller discharge stream and P g / V in viscous Newtonian and non‐Newtonian solutions.