Multi-GPU accelerated lattice Boltzmann modelling of melting performance for phase change material-metal foam composite considering interfacial thermal resistance

Metal foams are widely utilised to improve the energy storage efficiency of latent heat thermal energy storage (LHTES) by enhancing the effective thermal conductivity of phase change materials (PCMs). Meanwhile, the energy storage performance is hampered due to the interfacial thermal resistance (ITR) between PCM and metallic matrix. Aiming to address this problem, an LB method for the pore-scale solid-liquid phase transition considering the ITR is proposed. Based on the total-enthalpy-based LB formulation, a conjugate interface scheme is developed to tackle the interfacial condition. In this scheme, distribution functions across the conjugate interface are modified with an additional term related to the ITR during the streaming step. Inherently, the moving solid-liquid phase can be automatically traced without additional treatments of the latent heat source term. The numerical model is validated by the heat conduction with the ITR and convection melting problems. Using the metal foam with the body-centred-cubic cell (BCC) unit structure, a multi-GPU accelerated LB study is conducted to investigate the melting performance of the PCM-metal foam composite. The melting performance considering the ITR under different porosities and heating temperatures is comprehensively examined. Numerical results demonstrate that the higher porosity leads to a prolonged melting duration. The increases of the complete melting Fourier number (Fo_c) reach 29.46%, 23.71%, and 16.40% for ε = 0.85, 0.90, and 0.95 with R_i/R_bulk = 0.04 and the heating temperature T_h = 333 K. Accordingly, the relative deviations of Fo_c are 22.86%, 21.47%, 20.99% under ε = 0.90 and T_h = 343 K, 353 K, and 363 K, respectively. These highlight the significant delay in the melting process induced by the ITR, especially at lower porosities and heating temperatures. Therefore, the impact of the ITR under different porosities and heating temperatures on the LHTES system should be carefully considered.