Effect of supergravity on heat transfer characteristics of PCM with the pore-scale lattice Boltzmann method

Abstract

Latent thermal energy storage has been recommended as an effective technique to the thermal management system of space exploration due to its excellent ability of storing thermal energy. In the current work, the melting process of phase change material under supergravity conditions (3g, 5g, 7g) are numerically investigated by a pore-scale lattice Boltzmann method with the real microstructure of metal foam. A comparative study is carried out to illustrate the influence of gravitational acceleration and metal foam on melting performance of phase change material. Results indicate that natural convection accelerates the motion velocity of the upper PCM, and leads to the inhomogeneous distribution of melting front. Moreover, with the increasing gravitational acceleration, there is a transition of the dominated heat transfer mechanism from conduction to convection, which attributes to the stepped-up natural convection effect, and thus melting front gets even steeper and melting rate is significantly increased. Besides, the existence of metal foam significantly distorts the melting front and enhances the melting rate.