Triply periodic minimal surfaces (TPMS) have shown better mechanical performance, mass transfer, and thermal conductivity than conventional and strut-based structures, which have been employed in different disciplines. Most of the literature investigates different TPMS topologies in cooling channels to enhance thermal performance due to the smooth curvature and large surface area. However, a deeper investigation of the effects of TPMS design variables and the thermal performance advantages of cooling channels is required. This review details the effects of TPMS design variables, i.e., porosity, wall thickness, and unit cell size, on flow and heat transfer enhancement. It is found that varying the design variables significantly changes the flow and heat transfer characteristics. Also, by comparing TPMS and conventional cooling structures, it is found that most TPMS structures show better thermal performance than other strategies. Moreover, different fabrication methods for TPMS-based cooling channels in recent investigations are collected and discussed. In light of the reviewed literature, recommendations for future research suggest that more experimental and numerical studies on the flow and heat transfer for different cooling applications are needed. Therefore, this review serves as a reference tool to guide future studies on the flow and heat transfer of TPMS-based cooling channels.

An experimental investigation was conducted to quantify the characteristics of the turbulent boundary layer flows over a dimpled surface in comparison to those over a conventional flat plate. In addition to measuring surface pressure distributions to determine the friction factors of the test plates and to map the surface pressure inside the dimple cavity, a high-resolution digital particle image velocimetry (PIV) system was used to achieve detailed flow field measurements to quantify the characteristics of the turbulent boundary layer flows over the test plates and the evolution of the unsteady vortex structures inside the dimple cavity at the middle of the dimpled test plate. It was found that the friction factor of the dimpled plate would be about 30–80% higher than that of the flat plate, depending on the Reynolds number of the test cases. In comparison with those over a conventional flat surface, the flow characteristics of the turbulent boundary layer flows over the dimpled surface were found to be much more complicated with much stronger near-wall Reynolds stress and higher turbulence kinetic energy (TKE) levels, especially in the region near the back rims of the dimples. Many interesting flow features over the dimple surface, such as the separation of oncoming boundary layer flow from the dimpled surface when passing over the dimple front rim, the formation and periodic shedding of unsteady Kelvin–Helmholtz vortices in the shear layer over the dimple, the impingement of the high-speed incoming flow onto the back rim of the dimple, and the subsequent generation of strong upwash flow in the boundary flow to promote the turbulent mixing over the dimpled surface, were revealed clearly and quantitatively from the PIV measurement results. The quantitative measurement results are believed to be the first of its nature, which depict a vivid picture about the unique flow features over dimpled surfaces and their correlations with the enhanced heat transfer performance reported in previous studies.