CFD simulation of turbulence promoters in a tubular membrane channel

This study aims to investigate a computational fluid dynamics (CFD) simulation of a baffled tubular membrane channel containing a concentric rod for predicting turbulent flow. An array of baffles was inserted either on the rod or on the membrane wall for simulation. The qualitative and quantitative properties of fluid dynamics in a baffled membrane has been successfully predicted which is useful to understand better the flow pattern, behavior and feature. The distribution of local parameters such as stream function, velocity, static pressure, wall shear stress, turbulent kinetic energy, and turbulent dissipation energy upon the membrane surface was obtained using CFD code FLUENT. The simulation results indicate that the presence of baffle can improve the local shear stress on the membrane surface and produce eddy activities which enhance the filtration performance. The observed flux enhancement can be attributed to the intense fluctuations of wall velocity and shear stress which can disrupt the growth of boundary layer on the membrane surface. The experimental evaluation was performed through cross flow microfiltration of titanium dioxide suspension which is consistent with the CFD simulations. The simulation results under various baffle arrangements suggest the significance of baffle specifications for optimization of a baffled tubular membrane.

Research highlights
► Tubular membrane containing a rod and baffles achieved high wall shear stress.
► Baffle size and spacing are the factors that influence the local wall shear stress.
► Flux was significantly enhanced using a baffled tubular membrane.