仿真了氮气在温度为298 K,压强为20265.0~810600.0 Pa下的自发瑞利-布里渊散射光谱,利用仿真光谱研究了法布里-珀罗干涉仪的仪器函数线宽、散射角、气体体黏滞系数、压强参数误差,以及存在气溶胶时米散射干扰对气体温度反演结果的影响。仿真结果显示:在仪器函数线宽偏差≤5 MHz,散射角偏差≤0.2°,体黏滞系数偏差≤0.2×10 ^-5 kg·m ^-1·s ^-1,以及压强相对误差≤3%的条件下,单个参数偏差导致的温度反演的最大绝对误差为1.7 K。米散射的相对强度为0.3~2.5时,温度反演的误差通常低于2 K。此外,还开展了在温度为298 K,压强在70927.5~709275.0 Pa范围内的侧向90°的氮气自发瑞利-布里渊散射实验,经参数优化后,根据测量光谱对温度进行反演,结果表明:实验结果与仿真分析结论具有较好的一致性,在与仿真相同的参数误差条件下,实验获得的温度绝对误差小于1.2 K。该研究对实现不同压强条件下温度的高精度绝对探测及气体状态的准确分析具有一定的参考意义。

The Mie scattering interference induced by aerosol on gas temperature retrieval and the errors of line width of the Fabry-Perot interferometer (FPI) instrument function, scattering angle, gaseous bulk viscosity, and pressure are studied based on the spontaneous Rayleigh-Brillouin scattering spectra of nitrogen simulated at the temperature of 298 K and pressure range of 20265.0-810600.0 Pa. The simulation results show that when the error of the instrument function line width is less than or equal to 5 MHz, the error of the scattering angle is less than or equal to 0.2°, bulk viscosity error is less than or equal to 0.2×10 -5 kg·m -1·s -1, and relative error in pressure is less than or equal to 3%, a maximum absolute temperature error of 1.7 K caused by the single parameter error may occur. When the relative intensity of the Mie scattering is 0.3-2.5, the temperature retrieval errors are usually lower than 2 K. In addition, the spontaneous Rayleigh-Brillouin scattering experiment with a 90° scattering angle in nitrogen is performed at the temperature of 298 K and pressure range of 70927.5-709275.0 Pa. The temperature is retrieved according to the measured spectra after parameter optimization. The results show that the experimental results are in good agreement with those of the simulation. For simulation-based parameters with the same errors, the absolute temperature errors obtained by the experiment are lower than 1.2 K. This study is helpful in achieving the high-precision absolute measurements of gas temperature and accurate analysis of the gas state under different pressures.