CFD benchmarking of triply periodic minimal surface (TPMS) and non-TPMS heat sink geometries: Thermal-hydraulic trade-offs at equal structural volume

Lattice structures, particularly triply periodic minimal surfaces (TPMS), have attracted attention as heat sink designs due to their large surface areas and flow-disturbance effects. However, their thermal-hydraulic performance compared to conventional lattice and fin geometries under identical structural volumes remain underexplored. In this study, computational fluid dynamics (CFD) was employed to investigate flow behavior, heat transfer, and overall thermal-hydraulic performance of three TPMS geometries (Diamond, Gyroid, IWP), three non-TPMS lattices (simple cubic, body-centered cubic, face-centered cubic), and conventional fin heat sinks under two operating conditions: fixed Reynolds numbers (case 1) and fixed inlet velocities (case 2). Performance was assessed using Nusselt number, friction factor, Colburn j factor, and heat transfer rate per unit pumping power (Q/PP). Results show that TPMS structures enhance fluid mixing and achieve higher heat transfer coefficients, with the Diamond outperforming fins up to 71.29 %. Non-TPMS lattices exhibited lower hydraulic resistance and higher Nusselt number enhancements. The overall thermal-hydraulic assessment indicated that the SC geometry achieved the best balance between heat transfer and flow resistance, followed by FCC and BCC, while the Gyroid was the top-performing TPMS. Although TPMS offer structural and thermal advantages, non-TPMS lattices demonstrated superior overall efficiency across both cases, underscoring their potential for high-performance cooling applications.