Simulation of gas-liquid two-phase flow for airlift ceramic membrane filtration process

The influences of aerator aperture size and aeration rate on the gas hold-up, liquid circulation velocity, wall shear stress and turbulence intensity in a novel airlift ceramic membrane filtration equipment containing a 19-channel ceramic membrane was investigated by the CFD simulation. Further, the VOF model was adopted to simulate the flow state of the gas-liquid two-phase fluid and the mean error between experiment date and simulation date was 5%-10%. The results demonstrated that the gas hold-up increased with increasing aeration rate and decreasing aerator aperture size. The liquid circulation velocity, wall shear stress and turbulence intensity increased with increasing aeration rate, and the increasing trend became slow after the aeration rate reached 400 L·h^-1. For the three aperture aerator with different size, the comparison of experiment and simulation results have indicated that the liquid circulation velocity was only related to the aeration rate, and had little to do with aerator aperture size. Decreasing of the aerator aperture size was conductive to the increasing of the wall shear stress and the filtration process.