On the theory of bipolar charging of large aerosol particles

Abstract

The theory of bipolar charging of aerosol particles is developed for large particles (≥10 µm), taking into consideration the Coulomb field screening effect, which becomes relatively strong under conditions of high ion concentration attained in ionizers, (Formula presented.). The corresponding generalized kinetic model is based on the diffusion equations for positively and negatively charged ions migrating to the central particle in the collective electrostatic field with the potential obeying the Poisson equation (rather than the Laplace equation, as in the traditional approach). Direct numerical calculations show that the Coulomb field screening becomes especially important for very large particles, which can be eventually charged to the values, several times exceeding those calculated in the traditional approach. Copyright © 2018 American Association for Aerosol Research.