Numerical study on the anisotropy in thermo-fluid behavior of triply periodic minimal surfaces (TPMS)

Porous structures are frequently utilized as thermal conductivity enhancers in the realm of heat transfer enhancement. Triply Periodic Minimal Surface (TPMS) has gained significant attention in recent years due to its favorable performance in many fields including mechanics and thermodynamic. The exceptionally large specific surface area grants it promising performance in heat transfer enhancement. However, the angular effect on thermal-fluid characteristics are not understood and requires further investigation. In this work, Gyroid and Diamond with various rotating angles used as sandwich cores were designed utilizing the implicit function method. Then, the discussions on thermal and hydraulic behaviors in the TPMS-based sandwich panels under an isothermal condition were systematically conducted by means of computational fluid dynamics. After that, the fluid flow mechanisms and heat transfer properties were visually investigated according to the comparative analysis of velocity fields, pressure drops, vortices inducing, and Nusselt number distribution. The results showed that the flow field characteristics and the heat transfer performance exhibited an apparent 45° symmetry in both Gyroid and Diamond. Moreover, the pressure gradient exhibited evident dependence on the rotating angle in both Gyroid and Diamond groups. The 45° rotated Gyroid structure case had the most extensive pressure gradient of 11.4 kPa/m; to the contrary, the 45° rotated Diamond structure had the smallest one of 9.9 kPa/m in their respective group. Nonetheless, the angular difference in heat transfer rate (HTR) is not significant, and the maximum total HTR in Gyroid and Diamond groups was 8.25 W and 9.43 W, respectively. Overall, this work contributes to a better understanding of the angular behavior of TPMS-based sandwich panels and provides valuable information for their potential applications in various industries.