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The Research For Particle Concentration Measurement Technology Based On Laser Difference Detection

Posted on:2015-01-17Degree:MasterType:Thesis
Country:ChinaCandidate:Q HuFull Text:PDF
GTID:2268330428481673Subject:Optical Engineering
Abstract/Summary:PDF Full Text Request
As one of the important sources of pollution, the dust pollute the atmospheric environmental quality and human life. With the dust particles concentration monitoring become more and more important, relevant departments are developing high-precision testing instruments. This paper focuses on the problem of dust particle concentration detection and researches dust concentration measurement method based on laser differential detection, taking into account the appropriate scattering model to achieve an accurate measurement of the dust concentration. The study include the following:This paper introduces the composition of dust particle concentration detection system, and analyzes the attenuation principle of laser propagation in the dust particles. Particle concentration measurement based on laser difference detection is designed. The key parameter of measurement system is analyzed and selected.The physical characteristics of dust particles in the atmosphere and laser scattering properties and absorption properties in the particles are analyzed with Mie theory and Monte Carlo radiative transfer theory. The multiple scattering and absorption theoretical models are established in a media of random distribution particles. The relation between size distribution parameter of dust particles and particle population density and light intensity attenuation is obtained. The optimization detection wavelength is acquired by analyzing particle concentration and natural parameter of aerosol particle scattering and spectral absorption.Finally, based on the theoretical study, this paper uses the laser difference detection technique to measure optical attenuation due to scattering and absorption. The feasibility of detection system is certified by combining the results of theoretical research. According to the comparison result of the actual test and theoretical model calculation, the algorithm is majorized to implement accurate measuring about dust particle concentration in the atmospheric environmental.In this paper, the design of particle concentration detection has many merits, such as simple structure, high precision, not changing the physical and chemical properties of suspended dust and implementing automatic and continuous monitoring of dust concentration in the air. The result of research is also applicable to other industries field to detect the suspension particles at real-time.
Keywords/Search Tags:dust, concentration, difference detection, Mie scattering theory
PDF Full Text Request
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