Effect of bionic fin shapes on the melting performance of phase-change material (PCM) by numerical simulation

The bionic technology demonstrates the remarkable superiority in solving thermal engineering problems. To address the poor thermal conductivity of Phase-Change Materials (PCM), three typical bionic fins, including Snowflake Fins (SF), Tree Fins (TF), and Coral Fins (CF), were proposed, while three fin number was considered for each bionic fin in this study. A numerical simulation has been done to compare the melting process of PCM with three bionic fins in two-dimensional cavity by taking a refence of Rectangular Fin (RF). A transient two-dimensional model was established to reveal the relationship between fin morphology, heat transfer pathway evolution, and PCM melting behavior. The results demonstrate that the hierarchical branching structures significantly improve heat diffusion and promote the interaction between conduction and natural convection during PCM melting. Among the investigated structures, the CF exhibits the superior thermal performance due to its multi-level branching characteristics and enhanced heat transfer connectivity. CF showed the best heat transfer performance with reducing FMTs by 28.7%- 59.6% & 12.5%- 53.8%, increasing TRRs by 13.9%- 195.0% & 15.5%- 175.1% and increasing HSERRs by 31.5%- 58.6% & 13.6%- 54.3%, compared with SF and TF. This work provides a biomimetic design strategy for developing high-efficiency fin structures in PCM thermal energy storage systems.