十一组元高温平衡、非平衡空气光谱吸收系数计算

飞行器以很高的马赫数再入大气层时 ,头部激波层、尾迹的气体辐射产生的紫外、可见、红外特征信号 ,是地面监测和反导制导系统探测、识别的主要依据 ;同时 ,头部气体层热辐射也是再入体壁面加热热流的重要源项。激波层内高温气体吸收系数是目标紫外、可见光、红外辐射特性计算、热防护计算和气动流场辐射场耦合计算的基本参数。本文分析了再入过程中高超声速稀薄气体流的非平衡现象 ,采用三温度模型 (电子能温度 Te、振动能温度 TV、转动和平动能温度 TR)来表征激波层内非平衡态的气体组份各个能级占有数分布 ,并由原子分子辐射理论直接计算 N2 ,N+ 2 ,N,N+ ,O2 ,O+ 2 ,O,O+ ,NO,NO+和 e-等 1 1种主要空气组元各种能级跃迁对辐射的贡献 ,最终得到平稀和非平衡高温空气吸收系数计算模型。计算结果可见光区与试验结果符合较好 ,紫外、红外区结果稍差

Calculation of Spectral Absorption Coefficient of High Temperature Equilibrium or Non-equilibrium 11-Species Air

As a reentry vehicle traveling through atmosphere with a very high Mach number, the ultraviolet, visible light and infrared signatures, produced from its head shock wave layer and wake, are the foundation of detecting and identifying for the ground monitoring and the antimissile controlling and guiding system. At the same time, the gas layer radiation is also an important source of heating flux to the wall. The absorption coefficients of high temperature gas in the head shock wave layer are basic parameters for calculations of the target ultraviolet, visible light and infrared optical characteristics, the heat shield and the aerodynamic flow field coupling with thermal radiation. In this paper, after the thermo chemical non equilibrium phenomenon of hypersonic rarefied flow during reentry stage is discussed, a three temperature model (electronic temperature T e, vibrational temperature T V and rotational transitional temperature T R) is used to characterize energy levels population of non equilibrium air species in the shock wave layer and the contribution of 11 species such as N 2, N + 2, N, N +, O 2, O + 2, O, O +, NO, NO + and e - is directly calculated by using the atomic and molecular radiation theory. At last, a model is established, which calculates the absorption coefficient of high temperature equilibrium or non equilibrium air. The results are in good agreement with experimentally measured data in the visible region, but are slightly bad in the ultraviolet and infrared regions.