TDLAS气体检测系统调制系数的仿真及实验研究

发布时间：2018-04-04 08:37

本文选题：气体检测　切入点：可调谐二极管激光器　出处：《长春理工大学》2014年硕士论文

【摘要】：可调谐二极管激光调制光谱(Tunable Diode Laser Absorption Spectroscopy, TDLAS)技术目前广泛应用于工业生产以及环境污染监测等领域,以其高分辨率、快响应度、高灵敏度、低探测限的优势,在痕量气体检测的应用中得到了广泛的应用。随着各领域对TDLAS气体检测技术的需求逐渐增加,利用Matlab等数学软件来实现对TDLAS技术的模拟己经成为一个崭新的科研领域。利用虚拟平台对气体参量进行模拟,并进一步分析光学参量变化对测量的影响,会更好的描述TDLAS技术中的每个步骤,以便为相关实验提供参数设置的参考,更可以作为衡量TDLAS气体检测系统信噪特性的方法,使TDLAS技术在实际应用过程中更具可行性。利用Matlab软件编程实现了TDLAS气体检测系统的仿真模拟,为其在痕量气体检测的应用中打下了坚实的理论基础。气体吸收信号的模拟是基于Lambert-Beer吸收定律,利用Matlab编程模拟出气体直接吸收信号,其中气体吸收线所需的光谱信息是通过HITRAN数据库获取的。通过Matlab软件的仿真,建立起了基于可调谐二极管激光器的光谱气体检测系统的仿真模型。该仿真模型包括两部分：基础原理仿真部分和调制系数调节仿真部分,基础原理仿真部分主要为直接吸收光谱、调制吸收信号光谱和谐波提取图。调制系数部分是对理想模型的各系数进行调制,通过分析其变化得出参数范围。并通过对比仿真结果与预设值来验证仿真效果,调制系数的模拟工作是基于TDLAS气体检测技术的基本原理,推导出了TDLAS气体检测技术的谐波分量。本文利用Matlab编程实现了对直接吸收信号的调制和解调的模拟,最后通过实验对二次谐波幅度随调制系数变化进行验证,实验测量的结果与模拟结果基本一致,验证了对系统的模拟仿真。
[Abstract]:Tunable Diode Laser Absorption spectroscopy (TDLAS) technology is widely used in industrial production and environmental pollution monitoring, due to its advantages of high resolution, fast response, high sensitivity and low detection limit.It has been widely used in trace gas detection.With the increasing demand for TDLAS gas detection technology in various fields, it has become a new research field to use Matlab and other mathematical software to realize the simulation of TDLAS technology.Using the virtual platform to simulate the gas parameters and further analyze the influence of the optical parameters on the measurement will better describe each step in the TDLAS technology in order to provide a reference for the related experiments.It can also be used as a method to measure the signal-noise characteristics of TDLAS gas detection system and make the TDLAS technology more feasible in practical application.The simulation of TDLAS gas detection system is realized by using Matlab software, which lays a solid theoretical foundation for its application in trace gas detection.The simulation of the gas absorption signal is based on the Lambert-Beer absorption law. The direct gas absorption signal is simulated by Matlab programming. The spectral information required by the gas absorption line is obtained through the HITRAN database.The simulation model of spectral gas detection system based on tunable diode laser is established by the simulation of Matlab software.The simulation model consists of two parts: the basic principle simulation part and the modulation coefficient adjustment simulation part. The basic principle simulation part mainly consists of direct absorption spectrum, modulation absorption signal spectrum and harmonic extraction diagram.The modulation coefficient part modulates each coefficient of the ideal model and obtains the parameter range by analyzing its variation.The simulation result is verified by comparing the simulation result with the preset value. The simulation of modulation coefficient is based on the basic principle of TDLAS gas detection technology and the harmonic component of TDLAS gas detection technology is deduced.In this paper, the modulation and demodulation of the direct absorption signal is simulated by Matlab programming. Finally, the change of the amplitude of the second harmonic with the modulation coefficient is verified by experiments. The experimental results are basically consistent with the simulation results.The simulation of the system is verified.
【学位授予单位】：长春理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TP274;TN911.3

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