基于中红外吸收光谱技术的燃烧场CO浓度测量研究

Measurement of CO Concentration in Combustion Field Based on Mid-Infrared Absorption Spectroscopy

燃烧场组分的测量对于燃烧诊断具有重要的研究意义。基于可调谐激光吸收光谱(TLAS)技术,采用中红外带间级联激光器(ICL)扫描一氧化碳(CO)的2060cm^(-1)(v=1←0,P20)吸收谱线,实现了对燃烧场CO浓度的测量。实验通过燃烧产物H2O的7154.35cm^(-1)和7467.77cm^(-1)吸收谱线的谱线强度比值反演燃烧场温度,以此修正测量环境下CO谱线强度参数,实现CO浓度的精确测量。首先介绍了TLAS测温验证实验,温度测量在各个设置温度台阶下的波动均小于45K,温度测量具有可靠性;其次开展CO浓度测量标定实验,CO测量浓度与标准气体浓度的误差在3%以内;最后针对甲烷/空气平焰炉在不同燃烧状态下进行CO浓度测量,实现0.35‰~4.5%范围内CO浓度的测量,检测灵敏度为0.035‰。实验验证了中红外吸收光谱技术实现燃烧场组分浓度测量的可行性和可靠性,有助于燃烧诊断的研究,具有较大的应用价值。

The measurement of combustion components is significant for diagnosis of combustion.The study on measurement of carbon monoxide（CO）concentration in combustion field is realized with mid-infrared inter-band cascade lasers（ICL）at 2060 cm^-1（v=1←0,P20）to cover CO absorption line based on tunable laser absorption spectroscopy（TLAS）technology.In the experiment,the spectral line strength ratio between a pair of absorptions of water vapor（7154.35 cm^-1 and 7467.77 cm^-1）,for H2 O is the product of combustion process,is used to calculate the combustion temperature,that is used to correct spectral line strength of CO to achieve accurate measurement of CO concentration.Firstly,the TLAS temperature verification test is introduced,and the results show that the fluctuation of the test temperature is less than 45 Kat each set temperature step,which indicates temperature measurement is reliable.Secondly,the calibration experiment of CO concentration measurement is carried out,and measurement error of CO concentration is under 3% compared with standard gas concentration.Finally,the experiment achieves the CO concentration at the range of 0.35‰-4.5% on methane/air flat flame furnace under different combustion conditions,with a detection limit of 0.035‰.The experiment proves the feasibility and reliability of mid-infrared absorption spectroscopy technology to measure the concentration components of combustion field,which is helpful to the study of combustion diagnosis and has great application value.