Triply periodic minimal surface (TPMS) porous structures with great surface areas have the potential to enhance PCM melting. In this paper, melting behavior of phase change material (PCM) in a left surface heated rectangular container with four different TPMS structures was investigated and compared with that with the Kelvin structure. The pore-scale numerical simulation was developed to present the solid-liquid interface, temperature distribution, heat flux, PCM velocity, TPMS temperature and complete melting time. Results indicate that all TPMS structures have better conduction enhancement compared to the Kelvin structure, and thus lead to more uniform and faster melting. The conduction effect is significantly weakened with the increase of porosity and the convection is obviously strengthened with the increase of pore size. For all considered conditions, the Diamond TPMS structure results the best performance except at the porosity of 0.96. Compared to the Kelvin structure, the Diamond TPMS structure reduces the complete melting time by 47.0-75.5% and increases the power density by 178.1-275.0%. The I-WP TPMS structure shows the best melting performance at the porosity of 0.96, which saves 43.4% of complete melting time and increases 71.9% of power density.
Nie et al. (2026) studied this question.