Thermal-hydraulic performance of TPMS-based regenerators in combined cycle aero-engine

The existing regenerator structure in aero-engine cannot satisfy the requirements with the development of hypersonic vehicles. The triply periodic minimal surface (TPMS) with superior thermal and mechanical performances has great potential for the regenerator. However, the study on TPMS structures as heat exchangers with high compactness and high power-to-weight ratio is still lacking. This study presents a complete workflow for evaluating the performances of TPMS heat exchangers. Based on this workflow, the thermal–hydraulic performances of Diamond, Fischer-Koch S (FKS), and printed circuit heat exchangers (PCHE) at different Reynolds numbers are investigated. Compared with the PCHE, the performance evaluation criteria of Diamond and FKS structures increased by 11.3–26% and 10.9–32.5%, respectively. This can be mainly attributed to the intensive turbulent mixing, large wall shear stress and high specific surface area of the TPMS structures. The thermal–hydraulic performance is also well explained by the field synergy principle. Based on the developed thermal and hydraulic correlations, the TPMS regenerators are designed and the results indicate that the power-to-weight ratio is improved by about 4 times with half volume of a PCHE. In summary, the TPMS regenerators can save space, reduce weight, and increase payload of aircrafts and have great application potential in the field of aerospace.