Review of phase change heat transfer enhancement by metal foam

•Enhancement properties of metal foam on solid–liquid phase change and liquid–gas phase change heat transfer are reviewed.•The mechanisms and influencing factors of enhanced phase change heat transfer by metal foams are discussed.•Existing methods for optimizing phase change heat transfer performance within metal foam are classified and evaluated.•The practical applications of metal foam enhanced phase change heat transfer in recent years are summarized and compared.•The review provides a guidance for the design and application of efficient metal foam phase change heat transfer systems. Metal foam is a novel multifunctional material with high porosity, high specific surface area, and excellent heat transfer performance. Embedding metal foams into phase change heat transfer systems can be used to improve the comprehensive heat transfer performance, which is receiving increasing attention in the field of thermal management. This paper focuses on the lasted advances in solid–liquid phase change heat transfer and liquid–gas phase change heat transfer within metal foams, and specifically analyzes the influencingfactors on phase change heat transfer performance as well as the mechanism of metal foam effects on phase change heat transfer. Different optimized techniques for improving phase change heat transfer within metal foams and the current state of metal foam engineering applications for improving phase change heat transfer are reviewed and discussed. It is concluded that the addition of metal foam can significantly enhance the heat transfer performance of solid–liquid phase change systems and liquid–gas phase change systems, but it is accompanied by an inhibitory effect on natural convection, an obstructive effect on bubble overflow and an elevated effect on pressure drop. The application of gradient porous structure, metal foam fins, V-groove structure or changing the surface wettability of metal foam is a feasible way to alleviate the above problems. Meanwhile, it is pointed out that the phase change heat transfer performance within metal foam is influenced by the interaction of various factors, and some key issues regarding the influence mechanism of PCM-device orientation, pore distribution, surface wettability, and structural properties on heat transfer performance still need to be studied to develop more efficient and compact heat sinks.