利用输出波长在2.0μm处的分布反馈激光器对CO2气体的两条特征谱线进行扫描以实现气体温度的测量。介绍了利用可调谐激光吸收光谱方法进行温度测量的基本原理,提出了用多线组合非线性最小二乘法拟合高温吸收光谱的吸光度方法。常压下在静态高温炉中进行了实验,设定温度为900K~1200K时,经实验得到的温度值与热电偶测量值的温差在8%以内,计算得到CO2的5007.7874cm-1吸收线强与理论计算值相对误差小于14%。为今后的气体温度测量及多参数同时测量提供了借鉴。
Temperature measurement is realized by scanning two absorption lines of CO2 using distributed-feedback diode laser near 2.0 μm. The fundamental of temperature measurement by tunable diode laser absorption spectroscopy (TDLAS) is introduced, and multi-line nonlinear fitting method is proposed. The experiment is carried out in a heated static quartz cell at normal pressure. Within the temperature range from 900 K to 1200 K, the difference between TDLAS and S-thermocouple is less than 8%. Relative error between measured line-strength at 5007. 7874 cm-1 and the theoretical value is less than 14%. The result analysis can be useful for the further research on concentration and temperature measurement by a single diode laser.