Characterisation of Heat Transfer within 3D Printed TPMS Heat Exchangers

•The thermohydraulic performance of 3D printed TPMS heat exchangers were investigated.•A ray-tracing algorithm was developed for the thickness measurements of the walls.•A correlation was developed for the Nusselt number in the range 100 < Re < 2500.•The results of the study can be used for the design of micro-channel heat exchangers. Recent advances in additive manufacturing technology have enabled rapid and inexpensive prototyping of designs to explore shape effects across a range of engineering applications. In this work, we measure the heat transfer performance of a range of heat exchangers based on triply periodic minimal surfaces (TPMS). The results showed that the sheet gyroid TPMS design produced a high rate of heat transfer and moderate pressure drop. The sheet gyroid TPMS design was further investigated to determine its performance over porosities ranging from 40% to 85%, hydraulic diameters from 2 to 10 mm, and wall thicknesses from 0.4 to 2.6 mm. Our results show that all correctly parameterised TPMS of the same type have results positioned on the same Nusselt versus Reynolds number curves. A correlation was developed for the purpose of designing micro-channel heat exchangers over the operating range 100