Two-Phase Flow Modeling of a Dense Suspension

Liquid-solid mixtures (suspensions) are important in a variety of industrial fields, such as oil and gas refinement, paper manufacturing, food processing, slurry transport, and wastewater treatment. Several different modeling approaches have been developed by the CFD community, ranging from discrete, particle-based methods to macroscopic, semi-empirical two-phase descriptions.

This example illustrates how you can set up a macroscopic two-phase flow model in COMSOL Multiphysics using the Mixture Model application mode. The model accounts for not only buoyancy effects but also shear-induced migration; that is, the tendency of particles to migrate toward regions of lower shear rate.

The model simulates the flow of a dense suspension consisting of light, solid particles in a liquid placed between two concentric cylinders.

Surface plot of the particle concentration after 100 s. The arrows show the velocity field of the mixture.