Numerical Study of Heat Transfer and Performance in a Hydrogen-Fueled Micro-Combustor with Gyroid, Lidinoid, and Neovius Structures for Thermophotovoltaic Applications

This work evaluates a hydrogen-fueled planar micro-combustor featuring three triply periodic minimal surface (TPMS) structures, namely, gyroid, lidinoid, and Neovius matrix lattices, aiming to advance heat transfer processes and enhance system efficiency in micro-thermophotovoltaic (MTPV) applications. Through three-dimensional numerical investigations, a series of simulations are conducted under varying TPMS lengths, inlet volume flow rate, and inlet equivalence ratios to optimize the design and operating conditions. The outcomes reveal that increasing the length of the TPMS structures is an effective means of improving heat transfer from the combustion zone to the walls, as indicated by significant increases in both mean wall temperature and radiation efficiency. However, longer internal structures reduce the uniformity of wall temperature and slightly increase entropy generation. Of the three topologies, the Neovius lattice demonstrates superior performance in all length scales, exhibiting a marginal improvement over the gyroid and a substantially greater advantage over the lidinoid structure. Increasing the inlet volume flow rate enhances wall temperature and its uniformity; however, the performance parameters decrease for all structures, indicating a limitation of the micro-combustor in benefiting from higher input power. Notably, the gyroid structure shows a lower rate of performance degradation at higher velocities, making it a potentially ideal design under such conditions. Finally, varying the equivalence ratio identifies the stoichiometric condition as optimal, yielding superior performance metrics compared to both lean and rich mixtures.