Passage of Charged Particles Through Segmented Axial-Field Tubes

Abstract

We propose a mathematical theory explaining the passage of charged aerosol particles through segmented tube mobility filters recently suggested by Bezantakos et al. A segmented tube is composed of conductive segments and semiinsulating segments, which are made of electrostatic dissipative material. Electric potential applied to a semi-insulating segment generates a uniform electric field and holds back penetration of charged particles. Analytic equations of penetration efficiency of nondiffusing particles are derived for problems, where the length of the decelerating semi-insulating section exceeds the tube diameter at least twice and the air flow profile is uniform or follows the Hagen–Poiseuille law. The equations well explain the experimental results obtained by Bezantakos et al. The requirements for the tube parameters necessary for the application of analytic equations are derived by means of a numerical model. The motion of particles in segmented tube mobility filters is illustrated with diagrams co...