-
随着高速飞行器飞行速度的提升及空域范围的拓展, 其面临的气动加热环境愈发复杂, 绕流流场呈现出显著的热化学非平衡特性, 而现有数值模拟所依赖的基础热化学与输运模型在高焓非平衡条件下的物理准确性和适用性仍存在较大不确定性. 本文针对飞行器再入及高速巡航过程中激波层内的气动热化学非平衡问题, 系统开展了多组分输运性质计算方法的对比研究, 并分析了不同化学反应模型对激波后区域热化学动力学演化及辐射特性的影响. 选取高空高马赫数与低空低马赫数两种典型飞行工况, 对碰撞辐射模型(collisional-radiative model, CR)、Park模型和Gupta模型在激波后区域的预测结果进行对比分析. 结果表明, 在高焓、强非平衡条件下, 不同模型对主要中性组分(N2, O2, NO, N, O)及电离组分( \textN_2^+ , \textO_2^+ , NO+, N+, O+和自由电子)的数密度演化路径存在显著差异. 其中, CR模型预测的分子离解与原子电离过程相对滞后, 而Park模型与Gupta模型给出的离解和电离速率明显更快, 这种差异主要源于各模型在振动能级处理及非平衡能级分布假设上的不同. 在此基础上, 耦合逐线法辐射输运模型, 计算了真空紫外至红外波段的辐射系数, 综合考虑原子与分子体系中束缚-束缚、束缚-自由及自由-自由等辐射跃迁机制. 研究结果表明, 在高空高马赫数条件下, 不同化学反应模型预测的激波后辐射输运通量差异显著, 化学反应模型的选取对激波层内化学组成及辐射特性的准确预测具有重要影响.With the continuous increase in flight velocity and the expansion of operational airspace for high-speed vehicles, the aerodynamic heating environment they encounter has become increasingly complex. The surrounding flow field generally exhibits pronounced thermochemical nonequilibrium characteristics, which place higher demands on the accuracy and reliability of the fundamental thermochemical and transport data used in numerical simulations.This study focuses on the thermochemical nonequilibrium phenomena within the shock layer during atmospheric reentry and high-speed cruise of high-speed vehicles. Starting from a comparative analysis of multicomponent transport property calculation methods, the effects of different chemical reaction models on the thermochemical kinetic evolution and radiative characteristics in the post-shock region are systematically investigated. Two representative flight conditions—high-altitude/high-Mach and low-altitude/low-Mach regimes—are considered. A comparative analysis is conducted among the Collisional-Radiative (CR) model, the Park model, and the Gupta model with respect to their predictions in the post-shock region.The results show that under high-enthalpy and strongly nonequilibrium conditions, significant discrepancies exist among different models in predicting the number density evolution of major neutral species (N2, O2, NO, N, O) and ionized species ( \textN_2^+ , \textO_2^+ , NO+, N+, O+, and free electrons). Specifically, the CR model predicts relatively delayed molecular dissociation and atomic ionization processes, whereas the Park and Gupta models yield significantly faster dissociation and ionization rates. These differences mainly arise from the distinct treatments of vibrational energy levels and assumptions regarding nonequilibrium energy distributions in each model.On this basis, a radiative transfer model is further developed. The line-by-line (LBL) method is employed to calculate radiative coefficients across the spectral range from vacuum ultraviolet to infrared, accounting for bound-bound, bound-free, and free-free radiative transitions in both atomic and molecular systems. The results indicate that, under high-altitude and high-Mach conditions, substantial differences exist in the predicted post-shock radiative heat flux among different chemical reaction models. The selection of the chemical reaction model therefore plays a critical role in accurately predicting both the chemical composition and radiative characteristics within the shock layer.
-
Keywords:
- high-speed vehicles /
- non-equilibrium effects /
- chemical reaction models /
- radiative transport
搜索
x
中国物理学会期刊
下载: