基于空芯光子带隙光纤的全光纤甲烷检测系统研究

发布时间：2019-01-17 10:07

【摘要】：环境保护一直是全球所关注的热点,而甲烷是主要污染气体之一,不仅带来生产生活上安全与健康的问题,还是造成温室效应的主要气体。对甲烷浓度的实时在线检测,关系安全生产与健康生活。本文采用空芯光子带隙光纤制作气体传感探头,将光纤检测技术与谐波检测技术等弱信号检测技术相结合,设计甲烷光纤检测系统并实验验证。论文主要研究工作如下:(1)建立甲烷气体吸收谱数据库,分析并建立气体浓度计算模型。通过分析甲烷的分子谱理论,根据Hitran 2012数据库绘制甲烷分子吸收光谱图,建立甲烷气体浓度检测的数学模型,。(2)提出采用空芯光子带隙光纤作为气体传感探头的设计方案,设计甲烷气体检测系统的光路系统。研究空芯光子带隙光纤的传输特性,带隙效应与扩散速度,为构建光纤气室奠定理论基础。选择合适的带隙宽度等参数的空芯光子带隙光纤,比较两种扩散端面下的扩散时间,构建不同结构气室。(3)构建基于Labview的虚拟仪器的数据采集系统,实现对甲烷气体浓度的检测。进行甲烷气体光谱实验,吸收实验和评定实验等实验,实验结果验证了系统设计方案的可行性。(4)气体检测弱信号检测技术的相关研究。研究经验模态分解(EMD)及其改进的总体经验模态分解(EEMD)在光学信号检测上的应用,相对于小波降噪,从光谱图上主观评价以及通过参数标定,验证了数据处理的有效性。
[Abstract]:Environmental protection has always been the focus of global attention, and methane is one of the main pollution gases, which not only bring safety and health problems in production and life, but also cause the main gas of Greenhouse Effect. Real-time online detection of methane concentration is related to safe production and healthy life. In this paper, the hollow photonic bandgap optical fiber is used to fabricate the gas sensor. The weak signal detection technology, such as optical fiber detection technology and harmonic detection technology, is combined to design and verify the methane fiber detection system. The main work of this paper is as follows: (1) the methane absorption spectrum database is established, and the gas concentration calculation model is established. By analyzing the molecular spectrum theory of methane and drawing the absorption spectrum map of methane based on Hitran 2012 database, the mathematical model of methane concentration detection is established. (2) the optical circuit system of methane gas detection system is designed by using hollow photonic bandgap fiber as gas sensing probe. The transmission characteristics, bandgap effect and diffusion velocity of hollow photonic bandgap fiber are studied, which lays a theoretical foundation for the construction of optical fiber gas chamber. In order to construct different gas chambers, we choose the appropriate band gap width and other parameters of hollow photonic bandgap optical fiber, and compare the diffusion time between the two diffusion end surfaces. (3) A virtual instrument data acquisition system based on Labview is constructed. The detection of methane concentration is realized. The experiments of methane spectrum absorption and evaluation are carried out. The experimental results verify the feasibility of the system design. (4) the related research of gas detection weak signal detection technology. The application of empirical mode decomposition (EMD) and its improved total empirical mode decomposition (EEMD) in optical signal detection is studied. Compared with wavelet denoising, the validity of data processing is verified by subjective evaluation from spectral map and parameter calibration.
【学位授予单位】：燕山大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X84;TP274

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