Condensation on aerosol particles: Boundary element formulation

Local and global condensation rates of particles of arbitrary shapes are of interest in the studies of aerosol. The present paper is a follow-up on some recent work (Loyalka and Griffin, 1993, Nucl. Sci. Engng 114, 135; 1994, J. Aerosol Sci. 25, 509; Griffin and Loyalka, 1994, J. Aerosol Sci. 25, 1271) where it was shown that the relevant diffusion equation, with continuum and near-continuum boundary conditions, can be converted to an integral equation and then solved by a quadrature technique. Here the focus is on the application of a boundary element formulation to the integral equation. This numeric formulation is verified against analytical solutions for a spherical and a spheroidal particle. The formulation is then applied to a study of condensation on two wetted spheres with a liquid meniscus between them. Both the local and global condensation rates are calculated and the utility of an equivalent sphere approach is explored.