A fully conservative sharp-interface method for compressible mulitphase flows with phase change

A fully conservative sharp-interface method is developed for multiphase flows with phase change. The coupling between two phases is implemented via introducing the interfacial fluxes, which are obtained by solving a general Riemann problem with phase change. A novel four-wave model is proposed to obtain an approximate Riemann solution, which simplifies the eight-dimensional roo-finding procedure in the exact solver to a sole iteration of the mass flux. Unlike in the previous research, the jump conditions of all waves are imposed strictly in the present approximate Riemann solver so that conservation is guaranteed. Different choices of the fluid states used in the phase change model are compared, and we have shown that the adjacent states of phase interface should be used to ensure numerical consistency. To the authors' knowledge, it has not been reported before in the open literature. With good agreements, various numerical examples are considered to validate the present method by comparing the results against the exact solutions or the previous simulations.