基于频域吸收峰标定气体浓度的检测方法  

Detection method for calibration of gas concentrations based on absorption peaks in frequency domain

作　　者：柴金国 余善成 朱丹丹[1] 康立新 王正泰 徐露露 任俞宣 童凯[1] CHAI Jinguo;YU Shancheng;ZHU Dandan;KANG Lixin;WANG Zhengtai;XU Lulu;REN Yuxuan;TONG Kai(College of Electrical Engineering,Yanshan University,Qinhuangdao 066004,China;Ningbo Institute of Metrology and Testing,Ningbo 310018,China)

机构地区：[1]燕山大学电气工程学院,河北秦皇岛066004 [2]宁波市计量测试研究院,浙江宁波310018

出　　处：《应用光学》2024年第1期142-149,共8页Journal of Applied Optics

基　　金：河北省创新能力提升计划项目(22567619H)。

摘　　要：传统的光学气体检测方法需要将时域信号转换为频域信号,从而获得气体的浓度。这种方法在转换过程中会引入误差,无法准确反映频率随时间的变化,造成气体浓度不能准确标定。提出一种基于频域吸收峰标定气体浓度的检测方法。以CO_(2)为例进行检测,利用基于BeerLambert定律的直接吸收法对CO_(2)和N2的混合气体中CO_(2)的浓度进行测定。此方法通过采集激光束的光强和频率信息,并使用相邻平均法和Levenberg-Marquardt(LM)优化算法进行Lorentz拟合获得吸收光谱峰值强度。实验结果表明:激光峰值强度与气体浓度之间满足线性关系,Pearson相关系数可达0.999。因此,基于频域吸收峰标定气体浓度的检测方法可有效简化系统结构,避免时域到频域转换中频率漂移的影响,使得激光峰值强度与气体浓度之间线性度良好。The traditional optical gas detection method needs to convert the time domain signal to frequency domain signal to obtain the concentration of gas,which will introduce errors in the conversion process and cannot accurately reflect the change of frequency with time,resulting in the gas concentration cannot be accurately calibrated.A detection method based on frequency domain absorption peaks to calibrate gas concentration was proposed.Taking CO_(2)as an example for detection,the concentration of CO_(2)in the mixed gas of CO_(2)and N2 was determined by using the direct absorption method based on the Beer-Lambert law.This method obtained the peak intensity of the absorption spectrum by collecting the light intensity and frequency information of the laser beam and performing the Lorentz fitting by the adjacent averaging method and Levenberg-Marquardt(LM)optimization algorithm.The experimental results show that the linear relationship between laser peak intensity and gas concentration is satisfied,and the Pearson correlation coefficient can reach 0.999.Therefore,the detection method based on the frequency domain absorption peak calibration of gas concentration can effectively simplify the system structure,avoid the effect of frequency drift in the time domain to frequency domain conversion,and make the linearity between laser peak intensity and gas concentration good.

关 键 词：激光峰值强度 气体检测 频域吸收峰 频率漂移 

分 类 号：TN206[电子电信—物理电子学]