基于激光布里渊散射的高速气流测试技术

Measurement of high-velocity gas flow parameters using laser Brillouin scattering

激光布里渊散射是由介质密度涨落引起的一种非弹性散射现象,其散射谱特征参数(频移、线宽)取决于散射角和散射介质压强、温度等参数,通过探测高速气流激光布里渊散射谱,可反演获得高速气流压强、温度等参数。介绍了基于激光布里渊散射原理的高速气流参数测试原理,设计了一种基于法布里-珀罗干涉仪的高速气流参数测试装置,搭建实验平台获取了高速氮气气流的激光布里渊散射谱。实验结果表明,通过激光布里渊散射谱获得的高速气流压强、温度值与理论值相对误差在15%以内。

Laser Brillouin scattering is the result of the inelastic light scattering from the medium density fluctuations. The shape of the Brillouin scattering spectrum is dependent on the gas pressure, temperature, and the scattering angle. An effective non-intrusive method for measuring the temperature and pressure in gas flow was provided. The measurement principle of the high-velocity gas flow parameters by using laser Brillouin scattering was reviewed. A measurement device based on the Fabry-Perot interferometer （FPI） was designed to measure the Rayleigh-Brillouin spectrum of the gas flow, and the laser Brillouin scattering spectrum was obtained for a N2 gas flow. Experimental results show that the error of the pressure and temperature derived from the Brillouin scattering spectrum is less than 15% compared with the theory model.