A relaxation model for liquid-vapor phase change with metastability

TL;DR

This paper introduces a new dynamical system model for liquid-vapor phase change that captures metastable states and phase transitions, integrated into a two-phase flow model with numerical validation.

Contribution

It develops a relaxation model based on convex optimization of Helmholtz free energy to describe metastability in phase transitions, integrated into a two-phase flow simulation.

Findings

Model captures metastable and stable states effectively.

Numerical simulations demonstrate accurate phase transition representation.

The approach improves understanding of phase dynamics in fluid systems.

Abstract

We propose a model that describes phase transition including meta\-stable states present in the van der Waals Equation of State. From a convex optimization problem on the Helmoltz free energy of a mixture, we deduce a dynamical system that is able to depict the mass transfer between two phases, for which equilibrium states are either metastable states, stable states or {a coexistent state}. The dynamical system is then used as a relaxation source term in an isothermal 4$\times$4 two-phase model. We use a Finite Volume scheme that treats the convective part and the source term in a fractional step way. Numerical results illustrate the ability of the model to capture phase transition and metastable states.