CFD Modeling of Pulsed Disc and Doughnut Column: Prediction of Axial Dispersion in Pulsatile Liquid–Liquid Two-Phase Flow

Abstract

Numerical simulations of liquid–liquid counter-current two-phase flow in pulsed disc and doughnut columns (PDDCs) are performed. The simulation methodology comprises two steps. In the first step, the Euler–Euler method is used to obtain turbulent two-phase flow field. Turbulence is simulated by using standard k-ε mixture model. The dispersed phase is assumed to be monodispersed. The second step comprises solution of species transport equation together with flow equations to obtain residence time distribution (RTD) of the continuous phase. The RTD is used to estimate the axial dispersion coefficient or Peclet number of the continuous phase. Experimental data of RTD for different operating conditions (pulsing velocity, dispersed phase velocity, continuous phase velocity) and different geometries (diameter of the column, spacing between the discs) are used for validation. Estimates of the Peclet number by the CFD model are better than the same obtained from previously reported empirical correlations.