NUMERICAL STUDY OF THE FLUID-DYNAMICS AND MASS-TRANSFER OF AN ULTRAFILTRATION PERFORMANCE IN A TUBE MEMBRANE MODULE

A numerical treatment is presented for the pressure-driven ultrafiltration process of a solution flowing laminarly in a tube membrane module for variable permeation flux, high wall Reynolds numbers and incomplete solute rejection. Both the Navier-Stokes and diffusion equations are solved numerically in terms of finite differences using a boundary condition for the concentration on the membrane obtained from the balance of the rate of the solute arriving at the membrane and the sum of leakage and rate of back diffusion. Plots representing the membrane concentration, permeation velocity and fraction of solvent removed are provided.