Venturi-effect-inspired design of TPMS structures and their convective heat transfer characteristics

Triply periodic minimal surface (TPMS) lattice structures show great potential for compact heat exchangers and high-heat-flux electronic cooling owing to their high specific surface area, interconnected channels, and high geometric design flexibility. However, a single TPMS topology usually cannot simultaneously achieve high heat transfer and low flow resistance. To address this issue, this study introduces a Venturi-effect-inspired design strategy based on three typical TPMS structures: Gyroid, Diamond, and Primitive. Three composite structures, namely G-D-G, P-D-P, and G-D-P, are developed for inlet flow guidance, core heat-transfer enhancement, and outlet resistance reduction. In addition, two graded Diamond structures, V-Diamond based on volume-fraction variation and AR-Diamond based on aspect-ratio variation, are proposed. Conjugate heat-transfer simulations are conducted to evaluate the convective heat transfer coefficient j/f, Nusselt number, friction factor, and comprehensive heat transfer coefficient . Flow streamlines, temperature fields, velocity fields, vorticity, and turbulent kinetic energy are also analyzed to clarify the enhancement mechanisms. The results show that Diamond provides the strongest heat-transfer capability but with relatively high flow resistance; Primitive has the lowest resistance but weak heat transfer; and Gyroid offers a balanced performance. The V-Diamond and AR-Diamond structures enhance local flow acceleration and boundary-layer renewal through middle-region contraction. At Re ≈ 2000, AR-Diamond increases h, Nu, and j/f by about 26%, 17%, and 32%, respectively, compared with uniform Diamond, while reducing the friction factor by about 43%. Among the composite structures, G-D-P exhibits the best overall thermal-hydraulic performance, with a 55% lower friction factor than Diamond and 18%, 45%, and 157% higher j/f than Diamond, Gyroid, and Primitive, respectively. These results demonstrate that Venturi-effect-inspired graded and composite TPMS designs can effectively improve the balance between heat-transfer enhancement and flow-resistance reduction. This study provides a methodological reference for the structural design of high-performance heat sinks.