Coagulation Rate of Polydisperse Particles

Abstract

The coagulation rate of suspended particles is studied analytically, taking into account the effects of both the particle size and the size spread. The log normal function was utilized for representing a polydisperse size distribution. The continuum, gas-slip, and free-molecule regimes have been included in the study. As a result of the analysis, a series of comprehensive expressions are provided with which the particle coagulation rates in various Knudsen number regimes can readily be calculated. The results of the analysis show that the coagulation rate of a polydisperse aerosol is substantially higher than that based on a monodisperse size distribution model. The existing diagram showing the rate as a function only of the particle size or the Knudsen number has been expanded to include the polydispersity effects.