| With the rapid development of Chinese industrialization,the air pollution has become more and more serious,the high concentration of suspended particles in environmental pollution index was harmful to human health,so it is imperative to monitor the suspended particles in the environment.In this paper,aimed at the present situation and actual demand of domestic suspended particle detection instruments and Combined with the existing theories and methods of suspended particle detection at home and abroad,studying the suspended particle concentration detection system of laser scattering method and the accuracy of the system was verified by testing experiments.First of all,this paper analyzes the working principle of the two kinds of methods of monitoring and measuring instruments of suspended particulate matter sampling method and non-sampling method.Based on Mie scattering theory,the working principle of light scattering method for measuring the concentration of suspended particles was described.The effects of the wavelength of scattered incident light and the particle size of suspended particles and the refractive index of suspended particles on the distribution of scattered light intensity were simulated by MATLAB.The mathematical model of suspended sediment concentration was established based on Mie scattering theory,the genetic algorithm be used to inversion the mass concentration of the suspended particles with initial distribution of Johnson-SB particles,the simulation results show the correctness and reliability of the mathematical model.Secondly,the hardware structure and detection circuit of the particle concentration monitoring system based on laser scattering method were designed in this paper,The optical path system of semiconductor laser,a lens group and the aperture and the gas sampling subsystem in heating pipe,inlet,pressuresensor,air pump and gas filter body were designed arrcording to the Mie scattering principle and testing environment requirements.The hardware circuit design of suspended particle concentration detection is completed on the basis of the system hardware structure design.At last,the system of the particle concentration monitoring system based on the laser scattering method was systematically tested.The system test environment was a closed chamber,and the experimental results were compared with those measured by the standard scattering method and suspended particle concentration monitoring system based on the laser scattering method.The test data of the PM2.5 and PM10 standard particles were correlated with each other Analysis.The correlation analysis showed that there was no significant difference between the two methods.The accuracy of the measured data was improved by using MATLAB to establish the linear regression equation by using the two methods to measure the data.The error reason of data measurement based on the laser scattering method of suspended particle concentration monitoring system was analyzed and the solution was put forward. |
