The impact of chemical non-equilibrium models on the ultraviolet spectral radiation characteristics of shock layers

The primary purpose of this research is to analyze the impact of different chemical reaction models on the characteristics of NO ultraviolet spectral radiation in the shock layer of hypersonic vehicles. The study is conducted from two main aspects. Firstly, three different non-equilibrium chemical reaction models—Gupta, Park, and the modified Ozawa model—were used to simulate the non-equilibrium flow field in the shock layer of the vehicle. Secondly, we further analyzed the effects of different chemical reaction models on the formation of substances in the shock layer and the characteristics of NO ultraviolet spectral radiation. In this paper, we conducted an in-depth study and analysis using the typical flight case of the BSUV (Bow-shock Ultraviolet) flight experiment, which revealed that the non-equilibrium chemical reaction models in the shock layer significantly influence the concentration and distribution of substances, thereby affecting the ultraviolet spectral radiation. By comparing the computational results with the experimental detection spectra, the Park model showed better agreement with the experimental data, with a weighted error below 10%, outperforming the Gupta chemical reaction model. The Park model exhibits comprehensive performance in the current computational cases.