Hydrodynamic aspects of filtration antifouling by helically corrugated membranes

The important problem of fouling encountered in micro- and ultrafiltration can be drastically reduced by promoting turbulence close to the surface of the membrane. To this purpose, we have developed a new ceramic tubular memb rane geometry with a helical relief stamp at the membrane surface in order to maintain a high level of turbulence close to the surface during filtrati on. Microfiltration tests showed the efficiency of these new membranes and the effect of the stamp features. However, the actual mechanisms involved b y this helical relief are still unclear. Therefore, this hydrodynamic study was carried out to improve our knowledge both on antifouling phenomenon an d on the effect of the helical relief stamp on turbulence. The flow structure along a regular helical roughness and the: flow disturba nce induced by an inversion of the helix direction were characterized by ho w visualization and laser Doppler anemometry measurements. (C) 2000 Elsevie r Science Ltd. All rights reserved.