The coagulation of hydrosols by brownian motion and laminar shear flow

Abstract

The coagulation of hydrosols was investigated theoretically and experimentally. A reduced form of the particle size distribution function, designated “self-preserving,” was found to satisfy Smoluchowski's equations of coagulation by Brownian motion and shear flow. Brownian motion coagulation experiments with two heterogeneous hydrosols showed that the distributions were self-preserving. The rate of coagulation for heterogeneous systems was found to be second order in total particle concentration, consistent with the self-preserving form of the distribution function. Coagulation experiments were carried out in a simple laminar shear field using a homogeneous Dow polystyrene latex dispersion. Smoluchowski's shear flow theory was confirmed for shear rates ranging from 1 to 80 sec.−1 The shear coagulation of a heterogeneous emulsion was studied at several shear rates, and the size distributions were self-preserving