Two-phase CFD modeling of pulsed disc and doughnut column: Prediction of dispersed phase holdup

CFD simulations of Pulsed Disc and Doughnut Columns (PDDCs), which are used in solvent extraction based separation processes, are preformed to predict dispersed phase holdup in two-phase flow. Flow field is obtained by using Euler-Euler approach embedding continuity and momentum equations along with equations of the standard k-e mixture model of turbulence. The dispersed phase is assumed to be monodispersed. The momentum equation of the dispersed phase is modified to account for the effect of collisions among drops on dispersed phase holdup. The model is validated with in-house experimental data for different geometric and operating conditions. Predictions of CFD model are found to be better than the predictions of the reported correlations for estimating dispersed phase holdup in PDDCs. The validated computational approach is used for parametric analysis to understand the dependence of dispersed phase holdup and other hydrodynamic variables on operating and geometric parameters and scale-up methodology.