Abstract The present study aims to assess the performance of chemical rate models for species formation in the reacting shock layer flows over the blunt-cone hypersonic vehicles. Three 11-species nonequilibrium chemical models for air, Gupta 90, Park 93 and Ozawa’s modified models, are assessed. Two controlling temperature expressions (T0.5Tv0.5 and T0.7Tv0.3) for dissociation reactions are taken into account in these chemical kinetic models. To further examine the performance of these models for predictions of nonequilibrium effects and species formations in the shock layer, two typical flight cases are adopted: (1) the NO formation in reacting flows over the Bow-shock Ultraviolent (BSUV) vehicle at Mach number 17.7, and (2) the electron formation over the Radio Attenuation Measurements (RAM) C-II vehicle at Mach number 23.9 and 25.9. Firstly, comparisons of interested parameters between the computed results in different rate models and available reference data are carried out. Secondly, the reasons for the difference of species formations in these models are discussed. Results show that both the chemical rate model and the weight factor of the controlling temperature have a distinctive influence on species concentration and distribution in the shock layer. The weight factor determines the level of the vibrational-electronic temperature and the reaction release heat in nonequilibrium processes. With the increasing of the weight factor, the NO concentration increases and the electron density decreases in the same rate model. The spectral integration within the wavelengths of 205–255 nm shows that the prediction accuracy of the Park-0.5 and Ozawa-0.7 models is relatively high. Numerical results also indicate that the Ozawa-0.7 model may be an all-round model to predict electron formation in the shock layer.

中文翻译：

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非平衡空气化学模型对高超声速激波层物种形成的评估

摘要 本研究旨在评估钝锥高超声速飞行器上反应激波层流中物种形成的化学速率模型的性能。对空气的三个 11 种非平衡化学模型、Gupta 90、Park 93 和 Ozawa 的修改模型进行了评估。这些化学动力学模型考虑了解离反应的两个控制温度表达式（T0.5Tv0.5 和 T0.7Tv0.3）。为了进一步检查这些模型在冲击层中预测非平衡效应和物种形成的性能，采用了两个典型的飞行案例：(1) 马赫数下弓形激波紫外线 (BSUV) 车辆上反应流中的 NO 形成17.7 和 (2) 以 23.9 和 25.9 马赫数在无线电衰减测量 (RAM) C-II 飞行器上形成的电子。首先，对不同速率模型的计算结果和可用参考数据之间的相关参数进行比较。其次，讨论了这些模型中物种形成差异的原因。结果表明，化学速率模型和控制温度的权重因子对冲击层中的物种浓度和分布都有明显的影响。权重因子决定了非平衡过程中振动电子温度和反应释放热量的水平。随着权重因子的增加，在相同速率模型中NO浓度增加，电子密度降低。205-255 nm波长范围内的光谱积分表明Park-0.5和Ozawa-0.7模型的预测精度较高。