八面体桁架微元阵列隔热屏的流动换热特性的数值研究

To address the thermal protection challenges in extreme thermal load environment of afterburner combustion chambers， a novel thermal protection structure based on an octahedral truss microlattice array was proposed. The research systematically elucidated the internal flow and heat transfer characteristics along with their underlying mechanisms. An optimized segmented configuration was developed to accommodate the non-uniform outflow distribution of coolant. The effects of key parameters，including microlattice size， porosity， and pore diameter， on surface temperature distribution were comprehensively investigated. The results indicated that the structure with a porosity of 47.6% can enhance the overall cooling effectiveness of the wall surface by 2.75% compared with the structure with a porosity of 58.4%. Helium， as the cooling medium， exhibited the best cooling performance， with its comprehensive cooling efficiency on the wall surface being increased by 7.99% and 11.20% compared with nitrogen and air， respectively; the segmented transpiration structure enabled 28.6% reduction in coolant flow rate while maintaining equivalent cooling effectiveness. This study confirmed that optimized microlattice architecture combined with coolant parameter selection can significantly enhance overall cooling system performance， thus providing crucial theoretical guidance for designing high-efficiency thermal protection structures.