A modified mixture theory for one-dimensional melting of pure PCM and PCM/metal foam composite: Numerical analysis and experiment validation

Phase change materials (PCMs) have been attracting researchers’ attention in the last few decades for their great potential in energy storage. Nevertheless, the precise modeling of phase change problem of PCMs and PCM composites remains a problem due to the extra complexity generated by interactions between several constituents. In our study, we propose a modified mixture theory framework for one-dimensional pure PCM and PCM/metal foam composite melting problems, which allows us to study the thermal interactions between each constituent. In this modified mixture theory model, the local thermal non-equilibrium effect is considered, and the velocity correlated to the density change during paraffin melting is introduced. A new constituential heat flux term is presented to explain the heat supply from different constituents, and a new interpretation for internal energy supply term is introduced. The governing equations are numerically solved by using finite difference method. Temperature field, mushy zone evolution, and velocity profile at the boundary are predicted. Experiments are conducted to validate the numerical analysis. By comparing the temperatures at 4 positions, it is shown that the numerical results obtained by the mixture theory model have a satisfying agreement with the real situation.