Computational fluid dynamics modeling and experimental study of continuous and pulsatile flow in flat sheet microfiltration membranes

Abstract

Due to the significance of fluid flow hydrodynamics on the membrane surface, pulsatile flow was investigated as a functional approach to promote membrane performance. As a turbulence promoter, pulsatile flow in the membrane channel and its effects on the membrane performance were experimentally and numerically studied. A three-dimensional computational fluid dynamics (CFD) model was used to simulate cross-flow microfiltration process and fluid flow, including porous media by solving Navier-Stocks equations coupled with the Darcy's law. Two different boundary conditions were imposed at the module entrance: simple continuous fluid flow and pulsatile flow. Permeate flux, resistances, and shear forces were calculated in different operating conditions in which the experimental and simulated data showed a good agreement. It was found that shear force was the highest at the entrance region and then decayed along the flow direction for both continuous and pulsatile flow. Besides, two different types of pulsatile flow were considered; sinusoidal pulse flow and step function flow in which the latter led to higher shear forces and consequently higher permeate flux was obtained.