基于高斯/洛伦兹线型拟合比的谐波检测压强反演研究(特邀)  

Research on harmonic detection pressure inversion based on Gauss/Lorentz line fitting ratio(invited)

作　　者：高楠[1] 于永波 杜振辉[2] 李金义[3] 孟召宗 张宗华[1] Gao Nan;Yu Yongbo;Du Zhenhui;Li Jinyi;Meng Zhaozong;Zhang Zonghua(School of Mechanical Engineering,Hebei University of Technology,Tianjin 300130,China;State Key Laboratory of Precision Measuring Technology and Instruments,Tianjin University,Tianjin 300072,China;Key Laboratory of Advanced Electrical Engineering and Energy Technology,Tiangong University,Tianjin 300387,China)

机构地区：[1]河北工业大学机械工程学院,天津300130 [2]天津大学精密测试技术及仪器国家重点实验室,天津300072 [3]天津工业大学天津市电工电能新技术重点实验室,天津300387

出　　处：《红外与激光工程》2023年第8期159-166,共8页Infrared and Laser Engineering

基　　金：天津市自然科学基金项目(20JCYBJC00160)。

摘　　要：调谐激光吸收光谱(TLAS)技术具有非接触、抗干扰、高灵敏度等优势,可对气体进行浓度、温度、压强的测量。目前已有的压强检测模型中多以谱线的有限特征点进行提取与计算,存在易受干扰、测量误差较大的问题,因而有必要建立新的抗干扰、稳定性强的压强检测模型。针对此问题,文中根据吸收线宽的气体压力测量方法,提出了低压与高压范围内压强与谱线线型拟合函数的数学模型。结合谱线展宽原理,对不同压强下的二次谐波吸收线进行仿真研究。通过改变Gauss线型函数和Lorentz线型函数的半高宽比例关系模拟压强变化,分析信号拟合度的变化趋势,仿真结果表明,在理想情况以及激光器线宽、白噪声、背景干扰影响下,Gauss/Lorentz线型拟合度之比与压强之间存在三阶拟合关系,拟合度均保持在0.9980以上,且与传统模型相比在动态噪声和背景干扰下具有更好的稳定性。最后对CO_(2)气体1580 nm位置的实测信号进行处理,实验结果表明,实际检测谱线Gauss/Lorentz线型拟合度之比与压强之间的三阶拟合度为0.9863,略低于仿真的拟合度0.9987,符合仿真分析结果。文中提出的方法可以根据吸收谱线的拟合比曲线反演气体压强,为气体压强检测提供了解决方案。Objective Tuned laser absorption spectroscopy(TLAS)technology has advantages such as non-contact,antiinterference,and high sensitivity,which can be used for gas concentration,temperature,and pressure measurement.In the existing pressure detection models,limited feature points of spectral lines are mostly extracted and calculated,which can lead to problems such as susceptibility to interference in measurement results and significant measurement errors.Therefore,it is necessary to establish a new anti-interference and stable pressure detection model.To solve this problem,a mathematical model was proposed for fitting the pressure and spectral line shape function within the low and high pressure ranges based on the gas pressure measurement method of absorption line width.Methods Simulation research on the second harmonic absorption lines under different pressures was conducted based on the principle of spectral line broadening.In order to simulate the pressure changes by adjusting the Gauss/Lorentz halfwidth ratio,the second-order derivative signal was obtained by convolution of Gauss and Lorentz functions to simulate the second harmonic of the absorption spectral line.By establishing a mathematical model of the Gauss/Lorentz line fitting ratio and pressure,the fitting relationship between the two was obtained under ideal conditions and the influence of laser line width,white noise,and background interference.The comparative analysis on the stability of the fitting ratio with eigenvalues used to calculate pressure in existing models such as the peak width and 2f/4f amplitude under dynamic noise and background interference were conducted.Finally,the measured signal at 1580 nm of CO2 gas was processed to verify the simulation results.Results and Discussions The simulation results show that under ideal conditions and the influence of laser linewidth,white noise,and background interference,there is a third-order fitting relationship between the Gauss/Lorentz line fitting ratio and pressure,and the fitting degree remains

关 键 词：调谐激光吸收光谱 谱线展宽 曲线拟合 压强检测 

分 类 号：O433.4[机械工程—光学工程]