Lattice Boltzmann modeling of wall-bounded ternary fluid flows

TL;DR

This paper introduces a wetting boundary scheme within the lattice Boltzmann method for simulating ternary fluid flows near solid surfaces, demonstrating its effectiveness through various flow problems and an impact study on a solid cylinder.

Contribution

It develops a physically consistent wetting boundary scheme for ternary fluids in lattice Boltzmann simulations, enabling accurate modeling of complex fluid-solid interactions.

Findings

The scheme accurately simulates spreading and shear of ternary fluids.

Results agree well with analytical and existing numerical solutions.

Wettability and Weber number significantly affect compound drop dynamics.

Abstract

In this paper, a wetting boundary scheme used to describe the interactions among ternary fluids and solid is proposed in the framework of the lattice Boltzmann method. This scheme for three-phase fluids can preserve the reduction consistency property with the diphasic situation such that it could give physically relevant results. Combining this wetting boundary scheme and the lattice Boltzmann (LB) ternary fluid model based on the multicomponent phase-field theory, we simulated several ternary fluid flow problems involving solid substrate, including the spreading of binary drops on the substrate, the spreading of a compound drop on the substrate, and the shear of a compound liquid drop on the substrate. The numerical results are found to be good agreement with the analytical solutions or some available results. Finally, as an application, we use the LB model coupled with the present wetting boundary scheme to numerically investigate the impact of a compound drop on a solid circular cylinder. It is found that the dynamics of a compound drop can be remarkably influenced by the wettability of the solid surface and the dimensionless Weber number.