Numerical simulation of the dispersion of aggregated Brownian particles under shear flows

The deformation and breakup processes of a particle-cluster aggregate under shear flows are numerically investigated by the two-phase lattice Boltzmann method. The van der Waals attraction is considered to be the force between particles. Simulations are performed for various fluid forces acting on particles and various inter-particle forces. It is found that the ratio of the fluid force to the maximum inter-particle force, Y, is a key factor in dispersion, and the aggregate of non-Brownian particles is dispersed when Y is over 0.001. The Péclet number, which is the ratio of the diffusion rate due to shear flow to that due to the Brownian motion, is also considered. By comparing the calculated result of the dispersion of Brownian particles with that of non-Brownian particles, it is found that the Brownian motion impedes dispersion and the effect of the Brownian motion is remarkable when the Péclet number is under 105.