Electrically Enhanced Collection of Respirable Aerosols in Granular Bed Filters at Low Reynolds Numbers

Electrostatic augmentation is of specific interest in the capture of respirable aerosols which are too small for effective inertial separation and too large for significant removal by diffusion. A unit-cell model is used to examine the relative roles of inertia, interception, gravity, diffusion, and electrostatics in the capture of these particles at low Reynolds numbers. With low bed conductivities, very high applied field augmentation can be achieved, and the relative contributions from other mechanisms are small. Without a field applied to the bed, image charge forces do result in enhancement but contributions from mechanical mechanisms cannot be ignored.