Numerical study of melting of a phase change material (PCM) enhanced by deformation of a liquid-gas interface

Numerical simulations are performed in order to examine the time-dependent melting, and heavily deforming processes of phase change material (PCM) subjected to local heating. By comparing cases with and without deformation, the impact of the inclusion of a deformation model is firstly addressed to understand what influences the precise melting behavior. Mass, momentum and energy conservation equations are solved in a 2-D system based on a fixed grid by means of a finite volume method. The Volume of Fluid (VOF) method and the Enthalpy-Porosity method are applied to model the deformable liquid-gas interface and the melting processes, respectively. Results successfully show the melting, subsequent deformation and dropping-off behavior of the molten PCM. It is found that the inclusion of the deformation model enhances the melting owing to the increase of the total received heat; namely, widening of the contact area at the melting front and induced flow motion inside molten PCM improve the heat transfer toward the melting front. Parametric studies by varying the applied Stefan number so as to change the surface tension are also made to ensure the above-mentioned enhancement mechanism is universally applicable.