Excellent transpiration cooling performance of oriented porous structures for hypersonic vehicle leading edge

Transpiration cooling has been regarded as one of the most promising thermal protection technologies applied in the hypersonic vehicle engineering. Unfortunately, the transpiration cooling performance at the leading edge remains insufficient. In this work, a distinctive and effective transpiration cooling configuration adopting oriented porous structures has been innovatively proposed for regulating coolant distribution on the leading edges, and its remarkable cooling performance is numerically investigated. The research results indicate that higher orientation degree leads to an obvious reduction in stagnation temperature. The porous structure with fully oriented state (ε y ≤ 1 × 10 −4 ) achieves an optimal cooling performance, lowering stagnation point temperature by around 1000 K relative to traditional porous structure. Besides, increasing coolant flow rate contributes to a more prominent cooling improvement for the fully oriented structure than the traditional isotropic one. Nevertheless, it still exists an upper limit for enhancing cooling performance by increasing coolant flow rate because all coolant flows out near the stagnation point for the fully oriented porous structure. To address this issue, a novel multi-chamber transpiration cooling configuration adopting zonal porous structure with adjusted orientation degrees is proposed. In contrast to the conventional porous structure, the optimized configuration reduces maximum temperature by 48.26% and average temperature by 43%, and the stagnation-point cooling efficiency is elevated from 0.29 to 0.81. The research outcome in this paper can provide a significant theoretical reference to the transpiration cooling system design for the leading edge of hypersonic vehicle.