Thermofluidic transport in anisotropic metal foam: Low-velocity permeable flow, convection and solid–liquid phase change

• Prediction correlations for permeable flow resistance coefficients of MCPCM are proposed. • The interstitial heat transfer coefficient of MCPCM remains unaffected by the anisotropic structure. • An optimization scheme for arranging anisotropic foam structures can achieve synergistic improvement of convection and heat conduction. This work addresses the anisotropic thermofluidic transport characteristics of metal foam composite phase change material (MCPCM). To characterize the fluidic and thermal properties of anisotropic metal foam composites, representative elementary volumes (REVs) are obtained by directionally scaling isotropic templates numerically reconstructed from Weaire-Phelan foam cells. Direct numerical simulations of low-velocity permeable flow and interstitial heat transfer are then carried out. The viscous resistance coefficient, inertial resistance coefficient, and interfacial heat transfer coefficient of the REV are quantified under varying anisotropy ratios, porosities, and pore densities. Prediction correlations for the viscous and inertial resistance coefficients are proposed as functions of structural parameters, with deviations within 5% compared to experimental data from literature. Notably, the interstitial heat transfer coefficient is found to be insensitive to structural anisotropy, validating the applicability of existing isotropic heat transfer correlations for anisotropic MCPCMs. A macroscale solid–liquid phase change transport model is developed using the volume averaging method, incorporating the derived equivalent transport parameters and direction-dependent effective thermal conductivities reported in our previous work. The melting process of MCPCM is numerically analyzed under different foam arrangements. Results show that aligning the metal foam’s elongated direction perpendicular to the heating surface boosts the phase change rate by up to 18% under constant-temperature heating; parallel alignment performs better under constant heat flux, thanks to enhanced natural convection. These findings demonstrate that an optimal arrangement of anisotropic foam exists to simultaneously enhance convection and conduction, providing design guidance for high performance latent heat thermal energy storage and management systems.