The discrete unified gas kinetic scheme for solid-liquid phase change problem

The phase change material (PCM) receives more and more attention on account of the large amount of heat absorption and release during the process of phase change. In order to further investigate the heat transfer behavior of phase change, a discrete unified gas kinetic scheme (DUGKS) derived from Boltzmann equation for solid-liquid phase change has been developed in this paper. The phase change problems, including the phase change by conduction and by convection, are solved to verify the present DUGKS. The results of DUGKS agree well with that of analytical solution or benchmark solution. In the simulations of natural convection with phase change, the non-uniform mesh has been considered to evaluate the performance of DUGKS. Besides, no phase interface effect, with which the temperature is lower than the initial one in lattice Boltzmann (LB) method, is obtained in present DUGKS.