Applying a Modified Two-Fluid Model to Numerical Simulation of Two-Phase Flow in the Membrane Chlor-Alkali Cells

Abstract

In this study, gas evolution in a vertical electrochemical cell is investigated numerically with a modified two-fluid model. The mathematical model involves solution of separate transport equation for the gas and liquid phases with an allowance to inter-phase transfer of mass and momentum. The governing equations are discreted via the finite volume technique and then are solved by the SIMPLE algorithm in both the natural and forced convection states.In order to increase the accuracy of calculations, the power-law scheme is employed to approximate the convection-diffusion terms. Void fraction distribution of chlorine gas and velocity of both the gas and liquid phases are calculated. Also the effect of current density, electrolyte flow rate and space between the electrodes on the gas release are investigated. To verify this model, numerical simulations of a bubble-driven flow caused by the bottom injection of gas into a liquid bath is conducted. Comparisons between the predictions and the literature numerical datas illustrate that the predicted results satisfactorily agree with data available in the literature for both the liquid and gas phases.

Keywords

• membrane cells
• two-phase flow
• two-fluid model
• chlor-alkali
• numerical simulation