辐射加热对返回舱气动热环境影响的数值研究

Numerical study of radiative heating influence on aerothermal environment over a reentry capsule

基于高超声速再入飞行器气动热环境预测分析的需要,建立了高温非平衡气体辐射加热对飞行器热环境影响的计算分析手段。采用数值求解化学非平衡N-S方程的方法,对返回舱绕流流场进行模拟,获得高温空气组分质量分数和温度等流场参数分布。基于辐射传输方程,考虑高温气体组分的主要辐射机制,计算分析高温流场气体辐射加热对返回舱热环境的影响。分析表明,在同一飞行弹道条件下,返回舱大底半径尺寸对气动加热的影响较大,在再入热环境严酷区,辐射加热对物面总热流的贡献达30!;产生辐射加热效应的主要机制是高温流场中O和N原子产生连续谱和线状谱以及N2的第一正带系;物面催化效应对辐射加热影响不大。

The computational means are developed to predict the radiative heating influence of high-temperature nonequilibrium gas on the aerothermal enviroment in order to meet the require-ment of aerothermal enviroment understanding over hypersonic reentry vehicles.The high-tem-perature air flowfeild over a reenrty capsule after the lunar-earth transfer orbital flight are simula-ted by solving Navier-Stokes equations with chemical source terms,the parameters,such as tem-perature and mass fraction of species in the flowfilds,are obtained.Based on radiation transfer equation,considering the major radiative mechanisms of atoms and molecules in high temperature air,radiative heating influences on aerothermal environment of reentry capsule are studied nu-merically.The investigation indicates that the nose radius of the capsule has significant infulence on aeroheating with the given trajectory condition,and the radiative heat flux at local surface contributes over 30 percent of the total heat flux for those mostly severe aero-heating region.It also shows that catalytic effects on radiative heat flux is not so evident,the major radiative sources are the continual and line spectra of O and N,together with the first positive band of N2 .