A pressure-based diffuse-interface method for two-phase flows with mass transfer

We present a pressure-based method for the numerical solution of a four-equation two-phase compressible flow model with mass transfer. The model assumes kinetic, mechanical and thermal equilibrium and it is composed of the equations for the volume fraction, temperature, velocity and pressure. It includes the effects of viscosity, surface tension, thermal conductivity and gravity. Mass transfer is modeled through a Gibbs free energy relaxation term. A key feature of the proposed pressure-based methodology for the model system solution is the use of high performance and scalable solvers for the solution of the Helmholtz equation for the pressure, which drastically reduces the computational cost. Several numerical tests are presented to demonstrate the effectiveness of the proposed method, including tests involving flows with large density ratios, flows at low Mach number, and a challenging three-dimensional nucleate boiling simulation.