THE EFFECT OF WEAK GRAVITATIONAL FORCE ON BROWNIAN COAGULATION OF SMALL PARTICLES

The coagulation rate of a dilute polydisperse suspension of particles is considered for small Péclet number, which provides a measure of the ratio of the relative gravity-induced motion to Brownian motion between two rigid spheres. In particular, a four-term expansion for the dimensionless coagulation rate (Nusselt number) as function of the Péclet number is developed by making use of a singular perturbation method. In the limit of the radius of one of the two spheres becoming small, the result agrees with Acrivos & Taylor’s (1962) work on mass transfer to spheres at small Péclet number. © 1990, Cambridge University Press. All rights reserved.