基于CN自由基的火星再入流场温度测量  

TEMPERATURE MEASUREMENTS IN SIMULATED MARS ATMOSPHERES BASED ON THE CN RADICAL EMISSION SPECTRUM

作　　者：林鑫[1,2] 余西龙[2] 李飞[1] 张少华[1] 辛建国[2] 张新宇[1] 

机构地区：[1]中国科学院力学研究所高温气体动力学国家重点实验室,北京100190 [2]北京理工大学光电学院,北京100081

出　　处：《力学学报》2014年第2期201-208,共8页Chinese Journal of Theoretical and Applied Mechanics

基　　金：国家自然科学基金资助项目(11002148;9121610~~

摘　　要：利用氰自由基(CN)B2Σ+→X2Σ+电子带系的发射光谱温度测量技术诊断模拟火星再入流场高温气体的温度.以双原子分子光谱理论为基础,通过确定CN自由基B2Σ+→X2Σ+电子带系中?v=0振动带系发射光谱的跃迁波数、Einstein跃迁几率以及不同振转能级粒子数等参数,得到了任意转动温度和振动温度下的理论光谱强度分布,结合经窄线宽半导体激光器标定的仪器展宽(Lorentz线型,半宽度FWHM为0.154nm),为CN自由基B2Σ+→X2Σ+电子带系发射光谱测温技术提供理论依据.利用激波管模拟火星再入流场环境,通过分析激波波后不同时刻处高时间、空间分辨率的CN自由基发射光谱,得到了激波波后高温气体不同时刻处的转动温度和振动温度,并根据得到的温度信息给出了激波诱导时间和弛豫时间.Temperature measurements behind the strong shock waves for simulated Martian atmosphere were presented in this paper. Based on the inherent molecular structure characteristics of the CN radicals, the energy level distribution, the transition frequency and Einstein spontaneous emission transition probability were systematically analyzed and numerically studied. Meanwhile, the FWHM of apparatus function was measured experimentally to be Lorentzian profile of value O.lS4nm by using of a narrow line width diode laser. The dependence of the spectral structure on the rotational temperature and vibrational temperature were numerically analyzed in detailed. In shock-tube experiments, the emission of CN （B^2∑^＋→X^2∑^＋） system measurements were performed behind a strong shock wave in a CO2-N2 mixture with two different conditions of initial pressure and velocity. Rotational and vibrational temperatures behind the strong shock wave, and the radiation structure of the shock layer, including induction, relaxation and equilibrium processes were obtained through analysis of time gating optical emission spectra with nanosecond temporal resolution.

关 键 词：发射光谱 谱线强度 火星再入 转动温度 振动温度 

分 类 号：V556.4[航空宇航科学与技术—人机与环境工程]