Research On Light Scattering Measurement Technology Of Dust Particles

The dust particles in the atmosphere seriously endanger human health and property safety.The dust particles measurement have attracted the attention of the state.It is very important to realize the rapid and accurate measurement of dust particles in the fields of energy,materialogy,manufacture,chemical industry and environment.In recent years,the light scattering method has been widely used,as it has the advantages of simple measurement devices,high sensitivity and high precision.This paper research the Mie scattering theory,the Fraunhofer diffraction theory and the derivation about energy scattered distribution aiming at multi-particulate system,which realizes the calculation of the Mie scattering value in theory by the Lentz fractionation method.In the aspect of function constraint inversion algorithm,we first introduce the choice of regularization theory and its parameters.The inversion of traditional intelligent algorithm has problems that poor robustness and easy to fall into local optimum.For these shortcomings,this paper proposes a method,combining the regularization theory with bacteria foraging optimization algorithm.The objective function is constructed by introducing the Tikhonov smoothing function and the regularization parameters were determined by L curve method.Then search for the optimal solution of the function by using PSO and BFOA iterative calculation.The simulation results show that the particle size of BFOA is relatively successful,and the stability and the robustness are well.Besides,in the matter of unconstrained function method,the non-functional iterative method of NNPT algorithm is proposed.The analysis and comparison of the simulation results show that the NNPT inversion precision is improved and the stability is better after improvement.At the same time,the reasons for improvement of the coefficient matrix state also have been analyzed.This paper design and realize the dust particle measuring system and measuring software with the function of parameter settings,measure control,data acquisition,inversion calculation,displaying results and preservation.This system set up the experimental platform to carry out these measuring experiments to national standard particles.It turned out that the measurement system can successfully realize inversion of median size and its distribution in national standard particle.The inversion has the advantages of fast speed and high precision.The measurement D50 relative error less than 2% has been confirmed that conforms to the relevant national standards which the D50 relative error is within 3%.