Heat transfer tuning-oriented optimization and screening of triply periodic minimal surface structure-phase change material composites

Abstract

Phase change materials (PCMs) are ideal candidates for thermal energy storage systems due to their high latent heat, small phase change temperature fluctuation and excellent thermal stability. However, low intrinsic thermal conductivity represents a critical limitation that severely restricts practical engineering applications. In this study, three triply periodic minimal surface (TPMS) configurations (Diamond, Primitive and Gyroid) were generated via the implicit function method. By adopting the numerical simulation method and taking solid-liquid interface evolution, temperature distribution, average convective heat transfer coefficient and total melting time as the key indices, the structural optimization of TPMS-PCM composite systems was conducted for TPMS configurations, porosity and pore gradients. The simulation results showed that the Diamond-type TPMS-PCM exhibited the optimal heat transfer performance, with its total melting time reduced by 8.7% and 3.8% vs. Gyroid and Primitive configurations, respectively. The positive pore gradient structure outperformed uniform and negative structures, with the average convective heat transfer coefficient enhanced by a maximum of 8.1%. Visual experiments indicated that pure paraffin had a total melting time of 2179 s, and TPMS-PCM exhibited a drastically enhanced melting rate due to the superior thermal conductivity of TPMS skeletons, with the Diamond-type TPMS-PCM achieving a total melting time of only 320 s, an 85.3% reduction relative to pure paraffin. Moreover, synergistic regulation of porosity and pore gradient further accelerated PCM melting, cutting the time to reach solid-liquid phase-change temperature by a maximum of 20.5%. The established TPMS thermal optimization method underpins porous PCM composite parameter optimization, guiding their engineering preparation and high-efficiency thermal management design.