基于TDLAS的CO_2检测系统测量不确定度分析与评定

The measurement uncertainty analysis and evaluation of the CO_2 detection system based on TDLAS

可调谐二极管激光吸收光谱技术(TDLAS)相比与传统的光谱检测技术,其明显优势在于探测灵敏度高、选择性强、探测范围广、响应时间快,是目前气体检测常见方法之一。本文采用中心波长为1430nm的二极管激光器,应用波长调制光谱技术(WMS),在常温常压下对不同浓度的CO_2气体进行检测,对整个测量过程中的不确定度来源进行了详细讨论,并对各个不确定度分量进行了量化处理,最终得到其合成标准不确定度为0.3314,扩展不确定度为0.6628。对采集到的数据进行预处理,对其峰值大小与对应浓度作线性拟合,拟合系数为0.99931,并对拟合结果进行了验证,实验结果表明系统用于CO_2气体检测的可靠性,为WMS-TDLAS方法检测其它痕量气体的不确定度分析和评定提供了参考。

Tunable Diode Laser Absorption Spectroscopy （TDLAS） is one of the most common methods for gas detection at present,which is compared with the traditional detection technology.Its obvious advantages are high sensitivity,high selectivity,wide detection range,fast response time.In this paper,a diode laser with a central wavelength of 1430 nm is used to detect different concentrations of CO2 at normal pressure and temperature by using Wavelength Modulation Spectroscopy （WMS）.We focused on the sources of measurement uncertainty in the whole experimental process,then had a detailed analysis and quantized the uncertainty components.Finally got its synthesis standard uncertainty,which is 0.3314 and its expanded uncertainty is 0.6628.The collected experimental data were pre-processed by computer,of which the peak intensity was fitted to corresponding concentration linearly.The fitting coefficient was 0.99931 and the fitting results were verified.The experimental results show that the system is effective for the CO2 detection,and can provide a reference for the uncertainty analysis and evaluation of WMS-TDLAS method for detecting other gases.