Dielectrophoretic levitation in presence of shear flow: Implications on colloidal fouling control on textured channel walls

COLL 128

Subir Bhattacharjee, subir.b@ualberta.ca and Shahnawaz Molla, smolla@ualberta.ca. Mechanical Engineering Department, University of Alberta, Edmonton, AB T6G 2G8, Canada
The ability of dielectrophoretic (DEP) forces created using a microelectrode array to levitate particles in a colloidal suspension was studied experimentally and theoretically. The experimental system employs microfabricated electrode arrays on a glass substrate to apply repulsive DEP forces on polystyrene latex particles suspended in an aqueous medium. A numerical model was developed to calculate concentration distribution of colloidal particles in shear flow under the influence of a repulsive DEP force field. The results obtained from numerical simulations were compared against trajectory analysis and experimental data. The results indicate that by incorporating electric field induced DEP forces in a shear flow, particle accumulation and deposition on the flow channel surfaces can be significantly reduced or even completely averted. The mathematical model was then used to indicate how the deposition behavior is modified in presence of a permeable substrate, representative of tangential flow membrane filtration operations.