Research On Multi-component Gas Content Detection Technology Based On Photoacoustic Spectroscop

Based on the actual demand for on-line monitoring of dissolved gas in transformer oil,dissolved gas analysis technology in oil has been developed.Photoacoustic spectroscopy is widely used in this field because of its high sensitivity and stability.Based on the principle of photoacoustic spectrum gas detection technology,this paper explores the feasibility of using non resonant photoacoustic cell and infrared light source to replace today’s mainstream resonant photoacoustic cell and laser light source to realize high-sensitivity gas detection,designs a system that can realize multi-component gas content detection,and completes the gas detection experiment.This paper focuses on the photoacoustic spectrum gas detection technology,mainly from the following aspects:1.This paper introduces the research background and significance of photoacoustic spectrum gas detection technology,summarizes the research history and current situation of photoacoustic spectrum gas detection technology in China and abroad,and analyzes the basic principle of photoacoustic effect in detail,which provides an important theoretical basis for photoacoustic spectrum gas detection.2.Using the method of finite element analysis,the structure of non resonant photoacoustic cell is simulated by using pressure acoustic module,and the internal sound field distribution of photoacoustic cell in non resonant mode is explored,which provides theoretical guidance for the manufacture of photoacoustic cell.Then,the solid heat transfer module is used to simulate the heat conduction of the photoacoustic cell model.Based on this,the material of the photoacoustic cell is determined and processed.3.Based on infrared broadband light source and non resonant photoacoustic cell,a photoacoustic spectrum gas detection system is designed and built.The principle of processing weak signal by phase-locked amplification technology is introduced in detail,and it is simulated by MATLAB.Based on this theory,the design of photoacoustic signal processing circuit is completed.Using the development board based on STM32,the required functions of the system are programmed in C language,and the control circuit of each part of the system is designed.4.The influence of various factors on photoacoustic signal is analyzed and evaluated,and verified by experiments.The detection experiments of different component gases are carried out,and the detection of standard concentration gases is realized.