2.0 μm处CO2高温谱线参数测量研究

研究高温下待测气体的谱线属性, 如谱线强度、自加宽系数、空气加宽系数、温度系数等, 为高温环境中可调谐半导体激光吸收光谱技术反演温度、浓度、速度及其场分布提高精度和可靠性起着十分重要的作用. HITEMP数据库中的数据基本上是理论计算结果, 与实际情况存在相当的误差. 为了获得所选2.0 μm处的可用于燃烧诊断的CO₂谱线参数, 本文采用半导体激光器作为光源, 结合实验室的高温测量系统, 记录了700–1300 K温度范围内所选谱线的高温吸收光谱, 获得了各谱线在相应温度下的谱线强度、自展宽系数及温度系数等谱线参数. 测量得到CO₂的5006.978 cm^-1和5007.7874 cm^-1谱线强度与理论计算值相对误差小于11%; 获得了现有数据库缺少的温度系数和高温下自展宽系数数据. 所有各项参数对以后将要进行的燃烧诊断中的CO₂浓度检测有很大帮助. 关键词： 可调谐半导体激光吸收光谱 高温光谱 自展宽系数 温度系数

Study of CO2 spectroscopic parameters at high temperature near 2.0 μm

Reliable spectroscopic parameters of probed species at high temperature, such as line strengths, self-broadening coefficients, air-broadening coefficients, and temperature exponents, are important in absorption spectroscopy for accurately studying species properties, such as temperature, concentration, speed, and their corresponding field distributions. However, parameters from widely used database such as HITEMP are mainly theoretical calculation results, and there exist considerable errors compared with the results in actual situations. In order to validate spectroscopic parameters of CO₂ lines used in combustion diagnosis, CO₂ spectrum is recorded as a function of temperature in a range between 700 K and 1300 K in experiment using a distributed feed-back diode laser. Parameters of each line are deduced, such as line strengths, self-broadening coefficients and temperature exponents. The relative errors between measured and calculated line-strengths are less than 11% at 5006.978 cm^-1 and 5007.7874 cm^-1. The measured self-broadening coefficients at different temperatures and temperature exponents are conducive to the detection of CO₂ concentration in combustion diagnostics.
Keywords： tunable diode laser absorption spectroscopy high temperature spectrum self-broadening coefficient temperature exponent