Numerical modeling of solid-liquid phase change under the influence an external electric field

Abstract

Recent experimental results demonstrate that electric field can effectively decrease the melting time of dielectric Phase Change Materials (PCMs). In this study, a Finite-Volume Method (FVM) based numerical model for the solid-liquid phase change heat transfer of dielectric PCM under the influence of electric field is presented. Fully coupled governing equations of electric potential, charge transport, Navier–Stokes equations, and the energy equation are implemented in the finite-volume framework of OpenFOAM®. The numerical model is first validated against the analytical solutions for several test cases in the hydrostatic regime. Results from the numerical model exhibit good agreement with the analytical solutions. The numerical model presented in this work is capable of capturing the sudden step change in the charge density distribution and electric field due to the discontinuity of the physical properties at the interface. A numerical analysis of EHD assisted melting of a dielectric PCM inside a rectangular cavity is considered. Effects of electric Rayleigh number T and Stefan number St on the rate of melting are discussed. The transient evolution of the EHD assisted melting process which includes different flow stages is analyzed. It is found that the electric Rayleigh number T has a notable effect on the rate of melting and its influence is more pronounced at lower values of St. A maximum of 56.10% reduction in total melting time is achieved at T=3000 and St=0.01, for the flow configuration considered here.