EFFECTS OF INTER-PARTICLE INTERACTIONS AND HYDRODYNAMICS ON THE BROWNIAN COAGULATION RATE OF POLYDISPERSE NANOPARTICLES

Abstract

The Brownian coagulation rate of polydisperse nanoparticles by considering the effects of inter-particle interactions and hydrodynamics is studied in the gas-slip regime. The collision efficiency before and after particle contact is calculated by considering the van der Waals force, electrical repulsion, electrostatic force and elastic deformation force, respectively. It is found that the total collision efficiency decreases with the increase of both particle diameter and particle size ratio. Based on the total collision efficiency, the coagulation rate of polydisperse nanoparticles with considering the effects of inter-particle interactions and hydrodynamics is calculated. The results show that the coagulation rate with considering such effects is closer to the experimental data and much smaller than that without considering the effects. The inter-particle interactions and hydrodynamics make particles more difficult to coagulate and cause the coagulation rate to become weaker when the Knudsen number increases. The particles with high polydispersity coagulate more easily.