激发跃迁速率对热力学非平衡氮气紫外辐射的影响

Influence of excitation and transition rates on ultraviolet radiation of thermal nonequilibrium nitrogen

基于氮气的碰撞-辐射(CR)模型,计算了速度为6.2km/s、初始压力为133Pa的高超声速流动激波中N_2和N_2^+分子电子能级的分布情况,分析了不同激发跃迁速率模型对电子能级分布及辐射光谱模拟的影响。针对流动中热力学非平衡区域和平衡区域,在300～440nm的辐射光谱开展了逐线法的数值模拟,并与激波管实验测量光谱进行了对比。结果表明,目前的激发跃迁速率均存在偏差,综合Park模型的爱因斯坦系数和Johnston模型的碰撞激发速率可以得到与实验结果最为接近的辐射光谱。

Based on the collision-radiation(CR) model of nitrogen,the distribution of the electronic energy levels of N2 and N2+ molecules in the hypersonic flow shock wave with velocity 6.2 km/s and initial pressure 133 Pa is calculated. The effects of different excitation and transition rate models on the electronic energy level distribution and the radiation spectrum simulation are analyzed. A line-by-line method is carried out to simulate the radiation spectrum of the thermal nonequilibrium region and the equilibrium region in the 300-440 nm,which are compared with the experimental measurement spectra of the shock tube. It is found that the current excitation and transition rates all have deviations,and the CR model that integrated the Einstein coefficient of Park model and the collision excitation rate of the Johnston model can gain the radiation spectrum which is the closest to the experimental results.