Study on Nonequilibrium Plasma Discharge in Hypersonic Flow over Flat Plate

Hypersonic flow control with plasma discharge has received a good deal of research attention in recent years. In this study, the direct current (DC) plasma discharge over a flat plate was investigated as a prospective futuristic aerodynamic control device. Spectroscopic analysis showed that the vibrational temperature of nitrogen molecule is 7000 K and the translational temperature is 3500 K at maximum, which suggested that the plasma is at a vibrationally nonequilibrium state. Since electromagnetic forces for the futuristic aerodynamic control can mainly be imposed on ionized molecules, a numerical analysis was conducted based on Park’s Two-temperature model and Gupta’s 11-species model in order to estimate the distribution of high vibrational-temperature region. It was revealed that the concentration of high-vibrational temperature region exists in the boundary layer over flatplate surface, which is consistent with the experimental result of vibrationally exited nitrogen molecular distribution.

近年来，等离子体放电的高超声速流动控制受到了大量的研究关注。在这项研究中，对平板上的直流（DC）等离子体放电作为一种潜在的未来空气动力学控制装置进行了研究。光谱分析表明，氮分子的振动温度最高为7000 K，平动温度最高为3500 K，这表明等离子体处于振动非平衡状态。由于未来空气动力学控制的电磁力主要可施加于电离分子，基于帕克的双温度模型和古普塔的11种物质模型进行了数值分析，以估计高振动温度区域的分布。结果表明，高振动温度区域的浓度存在于平板表面的边界层中，这与振动激发的氮分子分布的实验结果一致。