| 基于光谱吸收原理的光纤甲烷气体检测研究电子书 摘 要 近年来，我国煤矿事故频繁发生，且以瓦斯爆炸为主，给矿工的生命和国家财产安全已造成严重威胁。甲烷是瓦斯的主要成分，及时准确地检测甲烷浓度对工矿安全生产和环境监测有着极其重要的意义。光纤气体检测技术是一种以光信号为载体、以光纤为信号传输通道的高灵敏度的气体检测技术。论文以甲烷气体检测为目的，进行基于光谱吸收原理的光纤甲烷气体传感技术的研究。论文首先介绍了各种光纤气体检测技术，回顾了光纤气体传感器的国内外研究现状和发展趋势，分析了光纤气体传感中的影响因素和关键技术。通过对分子光谱理论的分析，给出气体吸收测量的理论基础，并确定了甲烷气体的近红外吸收谱线，对其吸收特性进行分析，为传感器数学模型的建立奠定理论基础。其次，阐述了甲烷检测系统中光源、气室、光路部分和光电探测器的特性以及对测量的影响，设计了可以减小干涉噪声的小型渐变折射率透镜气室结构，并给出了检测微弱信号的锁相放大技术，实现了所测信号的提取和放大。最后，通过对甲烷探测系统中干涉噪声的研究，并利用Matlab 对其进行数值模拟，分析干涉噪声与气室长度、频率调制幅度等参数的关系。基于这种关系，合理选择测量参数能降低测量系统中的干涉噪声，对测量精度的提高具有重要的指导作用。为了补偿甲烷在近红外波段吸收弱的特点，采用灵敏度高的光谱调制技术。在现有的实验条件下，对光源光谱特性、甲烷近红外吸收特性、甲烷浓度检测及系统的重复性和稳定性进行了实验研究，实验结果验证了系统的可行性。 关键词 光谱吸收；频率调制；光纤气体传感器；小型渐变折射率透镜；干涉噪声；甲烷 目录 摘要 ···················································································································· I Abstract············································································································· II 第 1 章绪论·······································································································1 1.1 引言·········································································································1 1.2 气体检测技术的基本方法·····································································2 1.3 光纤气体传感技术·················································································3 1.3.1 吸收型光纤气体传感器···································································4 1.3.2 燃料指示剂型光纤气体传感器························································5 1.3.3 折射率变化型光纤气体传感器························································6 1.3.4 荧光型光纤气体传感器···································································7 1.3.5 多点复用型光纤气体传感器···························································8 1.4 光谱吸收式光纤气体传感器国内外研究现状······································9 1.5 课题研究的目的和意义·······································································11 1.6 课题的研究内容···················································································12 第2 章光谱吸收式气体检测机理 ·································································13 2.1 引言·······································································································13 2.2 气体分子光谱理论···············································································13 2.2.1 气体分子跃迁能级结构·································································13 |
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