In this work the hypersonic plasma flow generated by SCIROCCO hypersonic facility has been experimentally characterized as test case, using a high resolved Optical Emission Spectroscopy (OES) during a high enthalpy test campaign. The CIRA methodology to measure roto-translational and NO vibrational temperatures of a free jet via analyses performed in the Ultra Violet spectral range has been improved and a comparison between experimental data and Computational Fluid Dynamics (CFD) simulations has been carried out. The revised methodology estimates the roto-translational and vibrational temperatures using high definition spectroscopy carried out at conditions of high values of pressure and enthalpy.

In particular, attention is mainly focused on the NO emission band at Non-Local Thermal Equilibrium (NLTE) conditions in the hypersonic flight regime which means equilibrium between the molecular rotational and translational degrees of freedom but not between the roto-translational and vibrational degrees of freedom. Three tests at high enthalpy hypersonic conditions (23.8, 24.0 and 26.0 MJ/kg at a total pressure of about 2.5 bars) have been investigated and experimental data have been compared with numerical simulations in order to verify sensitivity of the method in estimating the small variation in NO roto-translational and vibrational temperatures by changing slightly the total enthalpy fluid-dynamic conditions. The current work presents a high definition spectral method which can be used to determine the temperature of NLTE hypersonic free jets, and may serve as a benchmark in determining the accuracy of various numerical models dedicated to these flow regimes.

在这项工作中，SCIROCCO 高超音速设备产生的高超音速等离子体流在高焓测试活动期间使用高分辨率光学发射光谱 (OES) 进行了实验表征。通过在紫外光谱范围内进行的分析来测量自由射流的旋转平移和 NO 振动温度的 CIRA 方法得到了改进，并且已经进行了实验数据和计算流体动力学 (CFD) 模拟之间的比较。修改后的方法使用在高压力和焓值条件下进行的高清晰度光谱估计旋转平移和振动温度。

特别是，注意力主要集中在高超音速飞行状态下非局部热平衡 (NLTE) 条件下的 NO 发射带，这意味着分子旋转自由度和平移自由度之间的平衡，而不是分子的旋转平移和振动度之间的平衡。自由。已经研究了高焓高超声速条件下的三个测试（23.8、24.0 和 26.0 MJ/kg，总压力约为 2.5 bar），并将实验数据与数值模拟进行了比较，以验证该方法在估计小变化方面的敏感性通过稍微改变总焓流体动力学条件，在 NO 旋转平移和振动温度中。