Effects of the number of particles and coordination number on viscous-flow agglomerate sintering

Abstract

The process of sintering of several particles in contact via a viscous flow mechanism was studied numerically using computational fluid dynamics. The volume of fluid technique within a finite volume method was used to simulate bridge formation between particles, as well as densification at different configurational states of the particles. The method was validated by comparing results for two-particle coalescence with the literature. The effect of the number of particles on agglomeration kinetics was studied by comparing bridge growth rate for systems having different numbers of particles in a chain. Although increasing the number of particles led to a decrease in the local bridge growth rate and to slower equilibration, there were no marked differences, when the overall volume of the system was considered. The effect of coordination number on the densification rate was directly studied by changing the number of particles in contact with a central particle. Increasing the coordination number caused the overall rate of densification to increase, but delayed equilibration, analogous to steric effects. These findings describe the configurational state of agglomerates, typical of mesoscale caking. In a multi-scale study, they can be used to characterize caking at a bulk scale to partly address the lack of experimental data in this field.