Effect of couple stress on ultrafiltration

Abstract

The effects of couple-stress and suction-Reynolds number on velocity and concentration distribution in the ultrafiltration process of a gel-polarization model are investigated. Both analytical and numerical techniques are used. The numerical method is based on an implicit finite difference scheme, and the analytical technique makes use of a regular perturbation. The calculations show that the effect of couple-stress is to inhibit the diffusive transport of solute molecules from the membrane surface to the bulk solution, in contrast to the suction effect. The ramification of the couple-stress in predicting the flux rates during ultrafiltration is examined.