Chemical-potential-based Lattice Boltzmann Method for Nonideal Fluids

TL;DR

This paper introduces a chemical-potential-based lattice Boltzmann model for simulating multiphase flows, improving efficiency and enabling control of wettability through surface chemical potential adjustments.

Contribution

The model directly evaluates nonideal force via chemical potential, satisfying thermodynamics and Galilean invariance, and allows linear tuning of contact angles.

Findings

Contact angle linearly tuned by surface chemical potential

Model satisfies thermodynamics and Galilean invariance

Improved computational efficiency by avoiding pressure tensor calculation

Abstract

Chemical potential is an effective way to drive phase transition or express wettability. In this letter, we present a chemical-potential-based lattice Boltzmann model to simulate multiphase flows. The nonideal force is directly evaluated by a chemical potential. The model theoretically satisfies thermodynamics and Galilean invariance. The computational efficiency is improved owing to avoiding the calculation of pressure tensor. We have derived several chemical potentials of the popular equations of state from the free-energy density function. An effective chemical-potential boundary condition is implemented to investigate the wettability of a solid surface. Remarkably, the numerical results show that the contact angle can be linearly tuned by the surface chemical potential.