Thermal-hydraulic performance evaluation of a novel cellular heat sink architected with hierarchical triply periodic minimal surface lattices.

Efficient heat dissipation is critical in the design of cooling systems to ensure device operation within the required temperature range. With the continued development of high-heat-generating devices such as microelectronic chips and power batteries, the exploration of novel heat dissipation structures is imperative. Triple periodic minimal surfaces (TPMS) have shown potential for efficient heat management. In this study, bioinspired hierarchical design principles are introduced to fabricate a novel solid-sheet hybrid two-order hierarchical structure, where first-order lattices (sheet TPMS cells) are arranged based on the topological structure of secondorder lattices (solid TPMS cells). Detailed three-dimensional numerical simulations are performed to investigate the flow characteristics and overall heat transfer performance of these hierarchical structures. The wellestablished Diamond structure, known for its superior performance, serves as a benchmark for comparison. Our results show a 20.3 % to 95.8 % improvement in the overall thermal performance of the hierarchical structure compared to the benchmark. The proposed hybrid structure also allows for increased wall thickness while maintaining the same porosity, which significantly reduces the resolution load on 3D printers. Furthermore, it is observed that the flow characteristics of the hierarchical structure are mainly influenced by the type of first-order lattice, while the heat transfer performance is significantly affected by the type of second-order lattice.