可调谐半导体激光吸收光谱(tunable diode laser absorption spectroscopy, 简称为TDLAS)技术具有高灵敏度、 快速响应、 非接触式、 环境适应性强等优点, 能够实现燃烧温度、 组分浓度、 速度等参量的实时动态在线测量。 为准确测量高温下的水汽浓度, 采用窄带半导体激光器作为光源, 结合实验室的高温测量系统, 记录了常压下1.39 μm附近水汽在773~1 273 K温度范围内的吸收光谱, 利用多线组合非线性最小二乘法拟合得到高温吸收光谱的吸光度, 找出了两条适合高温水汽浓度测量的吸收线7 154.35和7 157.73 cm-1, 首次提出高温水汽浓度测量的模型求解方法, 该方法测得的高温下水汽浓度符合理论推理, 浓度测量的标准误差低于0.2%, 相对误差低于6%。 通过实验验证了该测量方法的可行性。

Tunable diode laser absorption spectroscopy (TDLAS) has been developed to realize the real-time and dynamic measurement of the combustion temperature, gas component concentration, velocity and other flow parameters, owing to its high sensitivity, fast time response, non-invasive character and robust nature. In order to obtain accurate water vapor concentration at high temperature, several absorption spectra of water vapor near 1.39 μm from 773 to 1 273 K under ordinary pressure were recorded in a high temperature experiment setup using a narrow band diode laser. The absorbance of high temperature absorption spectra was calculated by combined multi-line nonlinear least squares fitting method. Two water vapor absorption lines near 7 154.35 and 7 157.73 cm-1 were selected for measurement of water vapor at high temperature. A model method for high temperature water vapor concentration was first proposed. Water vapor concentration from the model method at high temperature is in accordance with theoretical reasoning, concentration measurement standard error is less than 0.2%, and the relative error is less than 6%. The feasibility of this measuring method is verified by experiment.