中文摘要：

一氧化氮（NO）是高超声速飞行器流场中重要组分,对飞行器本体和流场红外辐射传输有重要影响,因此研究NO有效带宽的快速算法很有必要。根据HITEMP 2010数据库,研究了NO在1~15μm红外波段的谱线线强以及吸收系数分布特征,提出了改进的k分布模型,采用高斯数值方法快速求解;此外分析了吸收系数阈值对g-k曲线以及有效带宽的影响,提出了吸收系数阈值的选取方法。实验结果表明：文中方法计算得到的NO有效带宽与与逐线计算方法结果较为吻合,误差不超过5%;与宽带k分布算法相比,该算法计算效率更高,且当选择合适阈值时精度更高。

英文摘要：

Nitric oxide（NO） is one of the most important gas species in hypersonic vehicle ′s flow field,and has significant influence on infrared radiation transferring. Therefore, it ′ s necessary to acquire an efficient algorithm to calculate NO′ s equivalent band width. According to HITEMP 2010, the distribution characters of spectral lines and absorption coefficients of NO in infrared spectrum 1-15 μm were studied.Then an improved k-distribution model was proposed and the equivalent band width was solved by applying Gauss numerical scheme. Besides, the effects of absorption coefficient thresh on both g-k curve and equivalent band width were researched and the criteria of selecting the thresh was put forth.Experiments show that the results of the proposed algorithm agree with the ones obtained by line-by-line calculation, and the relative errors were less than 5%. When compared with the wide band k-distribution algorithm, the proposed algorithm has better computing efficiency and moreover it has better accuracy while using a proper thresh.