A relaxation model for liquid-vapor phase change with metastability

Abstract

We propose a model that describes phase transition including metastable states present in the van der Waals equation of state. From a convex optimization problem on the Helmholtz 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 4×4 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.