非分光红外瓦斯光谱吸收规律及其定量检测分析模型研究

The project takes the several unresolved problems that in the gas detection technology with non-dispersive infrared (NDIR) as the research object, and then explores the law of gas spectrum absorption with NDIR deeply.To solve the problem that it is difficult to calculate the complex optical path in multi-path, then through the optical path analysis, the model of optical path is abstracted. Through setting up the model of useful optical path absorption,thereby the law of gas spectrum absorption which under the conditions of complex multi-paths and non collimated light for non dispersive system are revealed.Study on non monochromatic spectrum absorption law. In order to solve the problems for the changes of temperature and pressure,various parameters are calculated and referred which based on the theories of quantum mechanics and spectrum absorption and the database of HITRAN. First of all,the calculation model of absorption coefficient which based on the temperature and pressure within single spectrum line is established,then the spectrum absorption law is used to each spectrum line.The model of total spectrum line absorption is set up by integration method of each line. Therefore the laws of gas spectrum absorption which based on temperature, pressure and non monochromatic light for non dispersive system are revealed. Finally a novel quantitative analysis model for gas spectrum absorption with non-dispersive infrared is proposed, and it is more effective and reliable for methane detection application.

本项目以非分光红外瓦斯检测技术中尚未解决的几个科学问题为研究对象，深入探索非分光红外瓦斯光谱吸收规律。针对多路径复杂光程难以计算的关键科学问题，通过光路解析，抽象出光路模型，建立整个有用光束的吸收计算模型，从而揭示某些非分光系统在复杂多路径非平行光条件下的瓦斯光谱吸收规律；研究非分光系统中非单色光的光谱吸收规律；针对温度压力变化等关键问题，根据基本量子力学理论、光谱吸收理论及HITRAN数据库等计算和查阅各种参数，先建立谱带内的基于温度压力的单个谱线的吸收系数计算模型，然后对每个谱线应用光谱吸收定律，采用逐线积分法，建立整个谱线的吸收计算模型，从而揭示非分光系统基于温度、压力和非单色光的瓦斯光谱吸收规律；通过科学规律探索，最终创新性地提出一种新的非分光红外瓦斯光谱吸收定量分析模型，为瓦斯检测奠定更加有效和可靠的应用基础理论。

本项目针对非分光红外瓦斯检测技术中尚未解决的几个科学问题进行了深入研究，取得了如下成果：提出一种非分光红外瓦斯传感器系统中漫反射光气体吸收计算模型和非单色光的光谱吸收计算模型，针对气体红外吸收的多路径复杂光程难以计算的关键科学问题，通过光路解析，抽象出光路模型，建立整个有用光束的吸收计算模型，根据基本量子力学理论、光谱吸收理论，通过对每个谱线应用光谱吸收定律，采用逐线积分法，建立整个谱线的吸收计算模型，揭示了非分光红外系统在复杂多路径非平行光及非单色光条件下的瓦斯光谱吸收规律；依据提出的计算模型，设计了红外光谱吸收式瓦斯检测仪，实验结果表明设计达到了预期目标，具有良好的应用前景；针对温度压力变化等关键问题，提出一种非分光红外气体传感器温压特性测试系统设计方案，并设计和实现了一个密闭的温度和气压可控的小型试验测试系统，用于仿真实验所需的环境温度和气压条件，对提出的模型和设计的传感器进行了验证，达到了预定目标，揭示了非分光红外瓦斯检测系统在复杂多路径非平行光、非单色光条件下基于温度、压力的瓦斯光谱吸收规律，为瓦斯检测奠定更加有效的应用基础理论；对所研究的成果进行推广应用于R134a制冷剂检测仪的研制,取得良好的效果。