Solid-liquid phase change in metal foam-enhanced PCM in thermal storage tank: A critical review on metal foam characterization, configuration, and numerical modelling

Metal foams possess high specific surface area, a three-dimensional interconnected structure, and excellent thermal conductivity, making them highly promising for enhancing the heat transfer efficiency of solid–liquid phase change heat storage systems. This paper systematically reviews the research progress in numerical simulation of metal foam-enhanced phase change heat storage systems. Through bibliometric analysis, the research trends and hotspots in this field are revealed. The classification of phase change materials and their thermal physical properties are summarized. Attentions have been paid to the key characterization parameters of metal foams, such as porosity, pore density, and matrix material. This study focuses on various filling patterns of metal foams, including complete, partial, gradient, and locally enhanced fillings. Besides, the mixed composite structures with nanoparticles, fins, and heat pipes are also quantified. This paper systematically reviews the mechanisms and optimization strategies by which these patterns influence the heat transfer and phase change behavior of the heat storage unit. The numerical simulation results show that metal foams can significantly improve the equivalent thermal conductivity of the system, but they also inhibit natural convection. Gradient structures and local filling designs can further optimize the heat field distribution and phase change uniformity. The composite use of metal foams with nanoparticles, fins or heat pipes can achieve multi-scale synergistic enhancement, significantly improving the system power density and response speed. Finally, this paper summarizes the limitations of existing strategies of filling patterns of metal foam for enhancing solid–liquid thermal storage. It proposes future research directions, providing theoretical references and forward-looking guidance for the design and optimization of high-performance phase change heat storage systems.