Thermodynamically consistent modelling and simulation of the moving contact line problem in non-isothermal compressible two-phase flows

TL;DR

This paper introduces a thermodynamically consistent model for non-isothermal compressible two-phase flows with moving contact lines, emphasizing temperature as a primary variable and ensuring adherence to thermodynamic laws.

Contribution

It develops a novel, thermodynamically consistent model based on the dynamic van der Waals theory, with new boundary conditions and numerical schemes that guarantee stability and physical fidelity.

Findings

Model satisfies first and second laws of thermodynamics

Numerical schemes are stable and thermodynamically consistent

Validated through numerical experiments

Abstract

According to the dynamic van der Waals theory, we propose a thermodynamically consistent model for non-isothermal compressible two-phase flows with contact line motion. In this model, fluid temperature is treated as a primary variable, characterized by the proposed temperature equation instead of being obtained from intermediate variables such as total energy density, internal energy density and entropy density. The hydrodynamic boundary conditions, which represent a generalization of the generalized Navier slip boundary condition in non-isothermal flows, are imposed on the proposed model. We then develop the dimensionless form of the model and prove that it rigorously satisfies the first and second laws of thermodynamics. Two numerical schemes based on the dimensionless system are constructed: one is fully coupled and thermodynamically consistent, namely strictly satisfying the temporally discrete first and second laws of thermodynamics; the other, designed by extending the multiple scalar auxiliary variable approach to entropy production, is decoupled, linear, and unconditionally entropy-stable. Several numerical results are presented to validate the effectiveness and stability of the proposed method.