Transpiration cooling with liquid phase change has been widely regarded as one of the most promising thermal protection technology for aerospace vehicles. However, when applied to the nose cone with small curvature radius, cooling failure may occur due to the extreme high heat flux and pressure at the stagnation point. In order to deal with this issue, a wedged-shaped nose cone structures with a gradient porosity layout is designed in this work to optimize the coolant distribution in the porous nose cone, and the corresponding transpiration cooling performance with liquid phase change is experimentally and numerically investigated. At last, to meet the thermal protection requirements under different flight conditions as best as possible, an orthogonal experiment and fuzzy gray analysis were carried out to optimize the particle diameter, porosity layout and division interval of the porous nose cone with gradient porosity layout, taking a specific flight condition as an example. The results obtained in this work showed that gradient porosity layout can significantly improve the cooling efficiency at the stagnation point and the temperature uniformity on the outer surface. The porosity has the highest impact on the cooling performance, while the division interval has little impact. By optimizing, the cooling efficiency at the stagnation point can reach 74.5%, and the maximum temperature difference is less than 500K.

中文翻译：

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梯度孔隙率布局蒸发冷却鼻锥热防护的实验和数值研究


液相蒸发冷却被广泛认为是航空航天器最有前途的热防护技术之一。然而，当应用于小曲率半径的鼻锥体时，由于驻点处极高的热通量和压力，可能会发生冷却故障。为了解决这个问题，本文设计了一种具有梯度孔隙率布局的楔形鼻锥结构，以优化多孔鼻锥中的冷却剂分布，并通过实验和数值模拟相应的液相变蒸发冷却性能。调查了。最后，为了尽可能满足不同飞行工况下的热防护要求，通过正交实验和模糊灰色分析，对梯度孔隙率布局的多孔鼻锥的粒径、孔隙率布局和划分间隔进行了优化，以特定的飞行条件为例。这项工作获得的结果表明，梯度孔隙率布局可以显着提高驻点冷却效率和外表面温度均匀性。孔隙率对冷却性能影响最大，而分割间隔影响不大。通过优化，驻点冷却效率可达74.5%，最大温差小于500K。