Thermo-hydraulic performance of DLP-fabricated TPMS inserts: Numerical and experimental case study

Triply periodic minimal surface (TPMS) architectures offer high surface area and interconnected flow pathways that are attractive for compact thermal management systems; however, their topology-dependent thermo-hydraulic behavior in additively manufactured low-temperature thermal absorber inserts remains insufficiently clarified under controlled geometric constraints. In this study, the thermo-hydraulic performance of DLP-fabricated Gyroid and Diamond TPMS inserts was numerically and experimentally investigated against a Rectangular Array reference for low-temperature thermal absorber applications. All inserts were designed with a wall thickness of 1.5 mm and a porosity of approximately 64% within a cylindrical domain, and were tested under forced-convection airflow over Re = 400-2000. A steady-state laminar CFD model was established and validated against experimental pressure drop and bulk temperature rise data, showing maximum deviations of 9.2% and 8.4%, respectively. The TPMS architectures induced stronger internal flow acceleration and mixing than the Rectangular Array, with peak velocities of 1.75 m/s for Gyroid and 1.97 m/s for Diamond, resulting in broader thermal spreading and stronger fluid-solid interaction. As a result, the heat-transfer coefficient increased from 68.43 to 128.40 W/m 2 ·K for Gyroid and from 75.28 to 144.56 W/m 2 ·K for Diamond, compared with 41.10 to 78.09 W/m 2 ·K for the Rectangular Array. Relative to the reference structure, Diamond and Gyroid enhanced the heat-transfer coefficient by 80.8-85.1% and 63.5-69.3%, respectively, although at the expense of higher hydraulic resistance. Overall, Diamond provided the highest thermal enhancement, whereas Gyroid offered a more balanced thermo-hydraulic compromise. These findings demonstrate that topology exerts a strong influence on the thermo-hydraulic performance of the investigated additively manufactured air-based low-temperature absorber inserts and provide practical guidance for balancing convective enhancement against pressure-drop penalty within the investigated forced-convection operating range.