Experiments and numerical analysis of turbulent flow heat transfer and pressure loss of a channel with triply periodic minimal surface structures

Triply periodic minimal surfaces (TPMS) have emerged as revolutionary geometric structures in the field of thermal management. Among these, the Gyroid and Diamond topologies, achieve outstanding in cooling channel design. This study investigates the endwall heat transfer and pressure loss characteristics in a turbulent-flow cooling channel embedded with the Gyroid and Diamond structures. The Gyroid and Diamond structures were additively manufactured with wall thicknesses ranging from 0.3 to 1.0 mm and porosities from 0.81 to 0.95. The endwall heat transfer distributions are acquired by transient liquid crystal thermography (TLC). Experimental results reveal that thicker walls expand high-heat-transfer regions, with Diamond exhibiting more symmetric distributions than Gyroid—though Gyroid achieves higher average heat transfer at identical thickness. However, both models show a decreasing heat transfer enhancement with the increase of the Reynolds number. The correlations of heat transfer augmentation and friction factor ratio are then formulated from the experimental results within the Reynolds number of 9000-33,400. At an equal pumping power, the total Nusselt number in the 1.0 mm-thickness Diamond structure is higher than all Gyroid structure by 9.52–18.1 %. Numerical simulations further demonstrate that Diamond's uniform flow field improves endwall heat transfer homogeneity, while Gyroid's velocity gradients cause non-uniform distributions. The high- and low-velocity flow phenomena in the Gyroid structure cause non-uniform heat transfer distributions throughout the channel.