通过LabVIEW软件设计一个基于TDLAS谐波检测含尘气体浓度的虚拟系统, 模拟测量在常温常压并含有已知粉尘颗粒的环境中SO2、NO2和NO 3种气体的浓度, 且使气体成分测量的结果不受粉尘因素的干扰。设计中使用2 516.2, 2 911.66, 3 752.44 cm-1的3种中红外激光分别对SO2、NO2和NO气体进行检测, 根据锁相放大原理设计虚拟多通道锁相放大器分析检测到的二次谐波信号, 根据谐波信号对各气体的浓度进行定标测量, 最后进行数据校正来排除粉尘颗粒的干扰, 使气体的定标测量得到一个稳定的结果。

A virtual system based on TDLAS to detect the concentration of dust containing gases was designed by LabVIEW. The concentration of SO2, NO2 and NO is measured at ambient temperature and pressure and environment of known dust particles, and the gas composition measuring results are not affected by dust. Three kinds of infrared laser of 2 516.2, 2 911.66, and 3 752.44 cm-1 are used to detect SO2, NO2 and NO. According to the principle of phase locked loop, the two harmonic signals detected by multi channel lock-in amplifier are analyzed, and the concentration of each gas is measured using the second-harmonic signal calibration. Finally, the interference of dust particles is eliminated through data correction, so as to get stable results.