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高超声速再入飞行器的热环境特性是热防护设计的重要基础。它主要包括辐射加热和对流加热,一般情况辐射加热较小可以忽略,但部分再入飞行器在低空还具有极高的速度,辐射加热不能忽略。本文针对高超声速再入飞行器驻点的辐射加热特性开展了研究,采用高温空气辐射加热的四光谱带模型,同时计算方法中考虑了非平衡辐射加热及其“截断效应”。计算结果表明,在低空高速再入阶段,辐射加热比较明显,热防护设计需要考虑辐射加热。辐射加热主要由可见连续光谱辐射构成,红外线谱和紫外线谱的辐射加热也比较明显,紫外连续谱辐射以及非平衡辐射效应均不明显。辐射加热沿球头驻点至球头外边缘逐渐减小,影响辐射加热的主要因素有头部半径、飞行高度和飞行速度。
The thermal environment characteristics of hypersonic reentry vehicles are an important basis for thermal protection design. It mainly includes radiant heating and convection heating. In general, radiant heating is negligible. However, some reentry vehicles also have extremely high speeds at low altitudes. Radiation heating can not be ignored. In this paper, the radiation heating characteristics of the hypersonic reentry vehicle stagnation point are studied. The four-band model with high temperature air radiation heating is adopted. The non-equilibrium radiation heating and its “truncation effect” are considered in the simultaneous calculation. The calculation results show that the radiative heating is more obvious at the low-altitude and high-speed reentry stage, and the thermal protection design needs to consider radiation heating. Radiation heating is mainly composed of visible continuous spectral radiation, infrared radiation and ultraviolet radiation heating is also more obvious, UV continuous spectrum radiation and non-equilibrium radiation effects are not obvious. The radiant heating decreases gradually along the ball head from the stagnant point to the outer edge of the ball head. The main factors that affect radiant heating are the radius of the head, the flight height and the flight speed.