Collection of prolate spheroidal aerosol particles by charged spherical collectors

Abstract

The effects of electrostatic forces and torques on the dynamics of prolate spheroidal particles are examined in relation to collision with a 30 μm radius collector droplet. When the non-spherical particles are uncharged the influence of the electrostatic torque can lead to either increases or decreases in collision efficiencies. Initial particle orientation is shown to be important for low collector charges but insignificant for high collector charges, when the electrostatic torque aligns the particle parallel to the electric field. For the charged particle case, where the Coulombic force is dominant, the collision efficiencies for particles having large aspect ratios are significantly lower than those for spherical particles. Depending on the particle and collector charge levels, both front and back capture modes are found. Image forces are shown to be insignificant for highly charged particles.