基于剩余幅度调制技术对强吸收下气体体积分数的测量研究  

Measurement of Gas Concentration under Strong Absorption Based on RAM

作　　者：程禾尧 王一红[1] 张辉[1] 周宾[1] 王浩[1] 汪步斌 熊涌泉 CHENG He-yao,WANG Yi-hong,ZHANG Hui,ZHOU Bin,WANG Hao,WANG Bu-bin,XIONG Yong-quan(School of Energy and Environment,Southeast University,Nanjing 210096,Chin)

机构地区：[1]东南大学能源与环境学院,江苏南京210096

出　　处：《仪表技术与传感器》2018年第6期92-96,共5页Instrument Technique and Sensor

基　　金：国家自然科学基金项目(50976024);国家自然科学基金青年科学基金项目(50906013)

摘　　要：在可调谐半导体激光吸收光谱技术中,可利用剩余幅度调制信号实现对气体参数的免标定测量。然而现有RAM方法均需做弱吸收假设和简化,同时引入复杂的修正函数以提取完整的透射率信号用于气体浓度反演。针对此问题,建立了适用于任意吸光度和调制系数下的傅里叶光谱吸收模型,提出了直接对背景信号归一化的一次谐波Y分量进行拟合的免标定算法,减少了重建吸光度引入修正函数的过程。使用CH4为目标气体进行实验,体积分数计算的相对误差小于2%,标准偏差均小于4×10-2%,验证了该方法的可行性。In the tunable diode laser absorption spectroscopy（ TDLAS） technology,calibration-free measurement of gas parameters can be realized by making use of residual amplitude modulation（ RAM） signal. However,the existing RAM methods are based on weak absorption hypothesis and simplification,and a complex correction function is introduced to extra the transmissivitysignal for gas concentration inversion. In this paper,a theoretical model of gas spectral absorption based on Fourier analysis was established,without the restriction of absorbance and modulation index. A calibration-free algorithm for fitting the Y component of the background signal normalized first harmonic signal was proposed,reducing the reconstruction of the absorbance and introduction of the correction function.The results show that the relative error of concentration measurement is less than 2% for methane concentration detection,and thestandard deviations are less than 4×10-2%,thus the feasibility of this method is verified.

关 键 词：可调谐半导体激光吸收光谱 剩余幅度调制 弱吸收 透射率 吸光度 调制系数 

分 类 号：TK314[动力工程及工程热物理—热能工程]