Modeling metal foam enhanced phase change heat transfer in thermal energy storage by using phase field method

A numerical study on the solid-liquid phase change in open-cell metal foams is carried out by the phase field method originated from the Ginzburg-Landau theory. The Brinkman-Forchheimer extended Darcy equation and the local thermal non-equilibrium model are adopted to take natural convection and the heat transfer between metal foams and phase change materials (PCMs) into consideration, respectively. The result proves that the phase field model is reliable and effective in modeling metal foam enhanced phase change heat transfer in thermal energy storage. The effects of key parameters, such as Rayleigh number, porosity and pore density, on the melting and solidification process are investigated and it is found that they have great influence on the solid-liquid phase change. The phase field, flow field and temperature distributions in the melting and solidification process are obtained. Furthermore, kinetic undercooling in the solidification process is studied. It is concluded that heat conduction through the ligament of metal foams plays a dominant role in the solid-liquid phase change and kinetic undercooling effect is weakened as kinetic coefficient decreases. (C) 2016 Elsevier Ltd. All rights reserved.