波长调制光谱中气体吸收率函数重构算法研究

项目名称： 波长调制光谱中气体吸收率函数重构算法研究

项目编号： No.51206086

项目类型： 青年科学基金项目

立项/批准年度： 2013

项目学科： 工程热物理与能源利用学科

项目作者： 彭志敏

作者单位： 清华大学

项目金额： 25万元

中文摘要： 由于无法获得气体吸收率函数，波长调制光谱技术一般需要通过二次谐波峰值进行复杂的标定实验来确定气体温度和浓度，且不能测量气体压力和光谱常数。本项研究利用谐波信号中丰富的气体吸收率函数信息，通过各次谐波信号重构出气体吸收率函数，进而根据气体吸收率函数直接确定气体温度、浓度、压力和光谱常数。研究通过吸收光谱理论和谐波理论推导出各次谐波X和Y轴信号的通项表达式，并根据该通项表达式建立谐波信号与气体吸收率函数的关系，利用各次谐波信号间的关系特征来消除背景信号、激光强度、调制系数等因素的影响，最终建立一种基于波长调制光谱技术的气体吸收率函数在线重构算法。重构算法拟通过数值模拟和物理实验进行验证和优化。本项研究预期可以精确重构出气体吸收率函数，使得波长调制光谱技术无需标定实验即可直接测量气体温度、浓度、压力和光谱常数，从而拓宽波长调制光谱技术的应用范围。

中文关键词： 可调谐二极管激光吸收光谱；波长调制法；气体吸收率函数；调制系数；

英文摘要： Wavelength modulation spectroscopy usually use the second harmonic peak and calibration experiments to determine the gas temperature and concentration, and can not measure the gas pressure and spectroscopic constants because this technique is difficult to obtain the gas absorption shape in actual measurements. Taking into account the harmonic signals contain a wealth of information on the gas absorption shape, this study intends to reconstruct the gas absorption shape by using these harmoic signals, and thus determines the gas temperature, concentration, pressure, and spectroscopic constants according to the measured absorption shape. Firstly, we have derived the X and Y axes expressions of each harmonic based on the absorption and harmonic theories, and the relationships between the harmonic signals and gas absorption shape have been established. And then, according to the relationships between the harmonic signals, the effects of the background signal, laser intensity, and modulation index have been eliminated. Finally, a Reconstruction Algorithm used to recover the gas absorption shape has been established based on wavelength modulation spectroscopy. The Reconstruction Algorithm to be verified and optimized through numerical simulation and physical experiments. This study is expected to reconstruct the gas ab

英文关键词： Tunable diode laser absorption spectroscopy；wavelength modulation spectroscopy；gas absorption shape；modulation index；