CFD Simulation of the Distribution of Pressure and Shear Rate on the Surface of Rotating Membrane Equipped with Vanes for the Ultrafiltration of Dairy Effluent

This paper reports computational fluid dynamics (CFD) studies on the performance of flow inside a rotating disk filtration module. This module consists of a disk rotating at speeds between 1000 and 3000 rpm inside a cylindrical housing equipped with a stationary circular flat membrane. In order to investigate the influence of surface geometry, a smooth disk and a disk equipped with vanes were used. Commercial CFD software was utilized for the characterization of the flow inside the membrane module. The predicted results were compared at different values of rotating and inlet velocities with previous works and also with experimental ones obtained in the filtration of dairy effluent in the same conditions. The influence of the geometry of the disk was also evaluated. The obtained results show that an increase in rotating velocity leads to an increase in the pressure and shear stress at the membrane surface. The highest pressures were obtained when using disks equipped with vanes, this was due to the turbulent area created between the vanes visualized in animated views. It was also found that the presence of vanes on the surface of disk has a great effect on the shear stress; it contributes to the reduction in fouling and improvement in filtration flux.