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 membrane geometry with a helical relief stamp at the membrane surface in order to maintain a high level of turbulence close to the surface during filtration. Microfiltration tests showed the efficiency of these new membranes and the effect of the stamp features. However, the actual mechanisms involved by this helical relief are still unclear. Therefore, this hydrodynamic study was carried out to improve our knowledge both on antifouling phenomenon and on the effect of the helical relief stamp on turbulence. The flow structure along a regular helical roughness and the: flow disturbance induced by an inversion of the helix direction were characterized by how visualization and laser Doppler anemometry measurements. (C) 2000 Elsevier Science Ltd. All rights reserved.