可调谐半导体激光吸收光谱法监测燃烧过程中CO浓度的变化

可调谐半导体激光吸收光谱技术(tunable diode laser absorption spectroscopy, TDLAS)是利用二极管激光器的波长调谐特性，获得被选定的待测气体特征吸收线的吸收光谱，从而对待测气体进行定性或定量分析。它具有高灵敏、高分辨以及快速检测等特点，已经广泛用于大气中多种痕量气体的检测以及泄漏气体的检测，也是在燃烧环境下对气体进行非侵入式实时测量的理想方法。TDLAS技术与开放式的多次反射池相结合，并利用自平衡探测加波长调制的新型检测方法，测量了酒精喷灯燃烧过程中产生的CO浓度，从测量结果中发现酒精喷灯火焰中CO的浓度成一定的周期性，并且得到火焰中CO的平均浓度为49.4(10-6体积比)。实验结果表明利用开放式多次反射池，结合自平衡探测加波长调制探测的新方法，满足了酒精喷灯燃烧过程中CO检测的需要，此系统为发展基于TDLAS的燃烧在线诊断技术奠定了基础。

Monitoring the Change in CO Concentration in Combustion with Tunable Diode Laser Absorption Spectroscopy

In the present paper,the technology of tunable diode laser absorption spectroscopy(TDLAS) in conjunction with the open path multi-pass Herriot cell and the new-style detection method of auto-balanced detection combined with wavelength modulation technology were used,and the concentration of CO produced in combustion of alcohol blowtorch was measured.It was found in the measured result that the change in CO concentration in the flame of alcohol blowtorch presented a stated periodicity in the process of combustion and the average concentration of CO was calculated to be 49.4(10-6 ratio by volume).The experiment is showed that with the conjunction of auto-balanced detection and the second harmonics detection method,adopting the open path multi-pass Herrriot cell to detect the concentration of CO in the combustion of alcohol blowtorch is accurate and contents the detection requirement.It was proved that the system made for measuring the concentration of CO in the flame of alcohol blowtorch in combustion establishes foundation well for developing on-line combustion monitoring based on TDLAS.