Flow Characterization in Triply-Periodic-Minimal-Surface (TPMS)-Based Porous Geometries: Part 2—Heat Transfer

Abstract

Complex physical phenomena take place while dealing with the convective heat transfer in porous medium. Due to involved complexities, most of the earlier numerical studies are performed using various porous models compromising the detailed phenomena. Therefore, a pore-scale simulation has been performed for convective heat transfer in triply-periodic-minimal-surface lattices, with identical void fraction and unit-cell size, but different geometrical shapes (tortuosity), namely Diamond, Inverted Weaire–Phelan, Primitive, and Gyroid. Further, each lattice derived into three different types of porous structures by designing second subdomain as solid (in Type 1), fluid (in Type 2), and microporous zones (in Type 3). The convective heat transfer in a square mini-channel filled with the porous structures is investigated for the range of flow Reynolds number \(0.01<\mathrm{Re}<100\) and \(\mathrm{Pr}=7\). The temperature distributions, solid and fluid Nusselt numbers on the external walls and on the internal walls, and quantitative departure from local thermal equilibrium (LTE) assumption are calculated for different porous media. The effect of porous morphology/tortuosity and effective porosity on the heat transfer is examined. The results revealed that the maximum temperature within the domain is found in Type 2 treatment, leading to inferior heat transfer performance compared to Type 1 and Type 3. Among all the lattices, the Diamond lattice provides more uniform temperature distribution over the external walls and within the volume including solid and fluid. The effective and the internal Nusselt numbers increase drastically for Re > 10. For the range of Re considered here, the Primitive lattice shows the maximum deviation from LTE assumption.