变温条件下水蒸气激光检测浓度反演及修正

Inversion and correction of water vapor concentration detected by laser at variable temperature

基于激光吸收光谱技术的气体浓度检测手段具有非接触、响应迅速和灵敏度高等优势,但在检测过程中气体对激光的吸收能力易受温度变化的影响导致浓度测量结果偏差增大。以水蒸气为研究对象,搭建了基于直接吸收光谱法的非常温条件(373~393 K)水蒸气浓度检测平台,提出了基于直接吸收光谱法的浓度反演修正方法。结果表明:修正后浓度测量值反演误差由原来最高35%降低至0.9%~3.5%范围内。

The gas concentration detection method based on laser absorption spectrum technology has the advantages of non-contact,rapid response and high sensitivity.However,on-line detection of industrial gas by laser spectroscopy is susceptible to temperature changes,resulting in an increase in concentration measurement deviation.In this paper,an experimental platform for water vapour laser detection at various temperatures(373—393 K)is built.The gas concentration is inverted by direct absorption method.The mechanism of temperature effect on the absorption spectroscopy characteristics of ammonia is explored,and a new method is proposed to correct the inversion concentration at various temperatures.The results show that the inversion error of concentration measurement value is reduced from 35%to 0.9%—3.5%.