高超声速飞行器热喷高温燃气红外辐射特性数值模拟

喷流反作用控制系统（Reaction Control System, RCS）热喷高温燃气辐射效应对飞行器光学探测跟踪具有重要影响。基于谱带辐射模型，通过求解带化学反应源项的三维Navier-Stokes方程和辐射传输方程，对高超声速飞行器喷流反作用控制系统热喷干扰流场及其红外辐射特性进行了数值模拟，分析了二次燃烧效应、不同飞行条件以及不同观测角度对流场红外辐射特性的影响。研究表明:典型状态喷流辐射计算与实验测量结果一致，流场与红外辐射数值方法具有较好的适应性；飞行器RCS工作所形成热喷干扰流场的红外辐射，主要由喷流燃气中的CO₂和H₂O组分贡献，其中CO₂对辐射的贡献更大，流场中二次燃烧效应对流场辐射强度有显著影响，在20 km高度下可使流场辐射强度提高一倍以上；随着马赫数/高度的增加，流场辐射强度均呈现先略有减小，后增大的趋势，随着高度增加，二次燃烧效应对流场辐射强度的影响明显减弱；由飞行器RCS工作引起的辐射增量十分显著，俯视观测以及3~5 μm波段的目标辐射强度最大。文中的研究结果可为飞行器探测跟踪提供参考。

Numerical simulation on radiation effect of hypersonic vehicle's hot gas jet

The radiation effect of reaction control system’s hot gas jet has an important role in optical detecting and tracking operations. Based on spectral band radiation model, and by solving three-dimensional Navier-Stokes equations with chemical reaction source term and radiation transport equation, numerical simulation of hypersonic vehicle’s RCS hot jet interaction flow field and its infrared radiation characteristics is performed, the influence of afterburning effect, flight condition and observation angles on radiation characteristics is studied. The result shows: Computational results compare well with experiment results in typical condition, which indicates the flow field and radiation computation method has good adaptability; Infrared radiation in flow field is mainly contributed by CO₂ and H₂O, where CO₂ contributes more, afterburning effect has significant influence on flow field radiant intensity, it can increase the flow field radiant intensity more than double at an altitude of 20 km; Flow field radiant intensity first decreases and then increases as flight velocity/altitude increases, as flight altitude increases, the influence of afterburning effect on radiant intensity sharply diminishes; The radiance enhancement caused by vehicle’s RCS plume is apparent, the radiant intensity at top view and 3-5 μm band is the strongest. These results can provide reference for further application in aircraft detecting and tracking.