.The permeate flux declination along an ultrafilter membrane is due mainly to the concentrationpolarization
resistance increment and the decline in transmembrane pressure. It was found in previous
works that the concentration polarization resistance could be reduced in a ring-rod tubular membrane
ultrafilter using the turbulent behavior. In the present study, the performance was further improved by
properly and gradually decreasing the baffled-ring distance along the cross-flow channel coupled with
properly adjusting the number of baffled rings. This theoretical analysis is based on the mass and momentum
balances as well as the application of the resistance-in-series model. The correlation predictions are
confirmed with the experimental results for dextran T500 aqueous solution ultrafiltration.