高超声速飞行器气动热辐射特性

Aero-thermo-radiation of a hypersonic vehicle

飞行器在大气层内高速飞行时,高速气体来流在飞行器顶端形成高温高压气体绕流,并对顶端光学探测窗口形成强烈气动加热,光学窗口温度急剧上升,高温气体和光学窗口的红外辐射对探测系统形成严重的气动热辐射效应,探测信噪比下降。针对非灰混合气体和光学窗口材料的辐射特点,采用介质辐射传输方法,模拟了钝锥球头外形头部且顶端安装探测窗口飞行器的气动热辐射,研究了气体和窗口热辐射随时间的发展及其与窗口材料的关系。结果表明,高温气体的热辐射与飞行器的运动状态关系密切,而光学窗口的热辐射随飞行时间增加而迅速增强,逐渐成为气动热辐射的主要因素,因此抑制光学窗口的温度上升速度和幅度是减弱气动热辐射的关键。

The flow field before a hypersonic vehicle flying in the atmosphere consists of high temperature and high pressure gas. The temperature of the vehicle＇s optical dome rises rapidly due to aerodynamic heating. IR radiation of the high temperature gas and dome bring severe aero-thermo- radiation effects which decreases the SNR of the detection system. According to radiation characteristies of non-gray gas mixtures and dome materials, simulation of the aero-thermo-radiation of a blunt cone body vehicle with sphere dome ahead was proposed based on infrared radiation transfer model. And then, the development of aero-thermo-radiation with time and different dome material were studied. The experimental results show that the high temperature gas radiant intensity is closely interrelated with the vehicle＇ movement, and the dome radiation increases rapidly with time, which becomes major factor of the aero-thermo-radiation gradually. Thus, restraining the velocity and range of the dome＇s temperature rising is the key to weaken aero-thermo-radiation effects.