Thermal effect of the anisotropic metal foam on the melting performance of phase change material: A pore-scale study

Recently, metal foams have been attractive in reinforcing the heat storage process of phase change materials (PCMs) beneficial from their high thermal conductivity, interconnected structure, and large specific surface. Nevertheless, the melting of PCM is not uniform caused by convective heat transfer, so it cannot be sufficiently accelerated by a traditional isotropic metal foam. In this study, we numerically investigated the melting performance of PCM in isotropic and anisotropic metal foams. Results illustrated that the X-anisotropic structure can more efficiently enhance the melting performance as compared to the isotropic original metal foam, but the Zanisotropic structure suppresses it. Moreover, the X-anisotropy-0.5 shows the fastest melting, its complete melting time is significantly reduced by 7.99 % compared with the original model, and its heat storage power is 8.68 % higher than the original one. Instead, the Z-anisotropic models prolong the complete melting time by 11.10 % - 28.55 %. It is owing that the anisotropic structure would promote the heat transfer along one direction but suppress its vertical direction. This article provides a feasible routine to accelerate the melting of metal foam-based PCMs, thus improving the heat storage power of the latent heat thermal energy storage system.