Gravity-induced flocculation of Brownian particles in quiescent media under weak gravity

The main scope of the present paper is to study the rigorous problem of coupled gravity-induced/Brownian flocculation for the strong Brownian/weak gravity case, by solving the coupled Langevin type equations on determining the Brownian particles' collision trajectories. When comparing with the previous results, our numerical calculated flocculation rates are as good as those solutions obtained from using the singular perturbation expansion method to solve the steady state governing convective diffusion equation. Our solutions also confirm that the effect of Brownian diffusion can decrease the flocculation rates of colloidal particles under the condition of strong Brownian/weak gravity.

The dimensionless interaction force diagram between two approaching particles. From this figure, it can be found that the relative magnitudes of (Fint∗∗)max and −(Fint∗∗)sec and the particle's NGNG value determine the particle flocculation behavior.Figure optionsDownload high-quality image (37 K)Download as PowerPoint slide