title: Effect of hydrodynamic interactions on rapid Brownian coagulation of colloidal dispersions.
abstract: The rate of rapid Brownian coagulation is investigated for dispersions of spherical particles with particle volume fractions ranging from Øp = 0.003 to 0.1 by the direct numerical simulation method. This method explicitly considers hydrodynamic interactions (HIs) between particles by simultaneously solving for the motions of the dispersed particles and the host fluid. In the dilute limit, the rate of rapid Brownian coagulation decreases to approximately 0.3-0.5 times the theoretical Smoluchowski rate. We compare this result with results of previously reported experiments and theoretical predictions and find a strong correlation between them. This demonstrates that HIs between particles significantly reduce the coagulation rate. Moreover, the volume fraction dependence of the coagulation rate indicates that the coagulation rate increases with increasing volume fraction. At high particle volume fractions, the initial coagulation stage is affected by heterogeneous coagulation process before the steady state is reached.
authors.affiliation: Production Engineering Research Laboratory, Sumitomo Bakelite Co, Ltd, Shizuoka 426-0041, Japan. ymatsuoka@sumibe.co.jp
authors.forename: Yuki
authors.initials: Y
authors.lastname: Matsuoka
authors.forename: Tomonori
authors.initials: T
authors.lastname: Fukasawa
authors.forename: Ko
authors.initials: K
authors.lastname: Higashitani
authors.forename: Ryoichi
authors.initials: R
authors.lastname: Yamamoto
mesh_terms: D003102:Colloids / Q000737:chemistry*; D003198:Computer Simulation; D004058:Diffusion; D057446:Hydrodynamics; D008956:Models, Chemical; D008958:Models, Molecular; D014867:Water / Q000737:chemistry*
chemical_list: D003102:Colloids; D014867:Water