The Research Of Particle Size Distribution Detection Based On Mie Scattering Theory

Particle detection is a multidisciplinary technology which is widely used in many fields. Solid particles such as dust, pulverized coal, catalyst, as well as gas particles such as bubble, are important parameters in many fields such as air pollution detection, production emissions detection, oil refining, textile fiber strength testing and other testing fields respectively. Size detection of the particles is one of the most basic, but also the most important aspects. At present there are many ways to detect the size of the particle. Optical method is taken as an important particle detection method with smaller interference, larger detection range, quicker detection speed and more easily to be realized automation. At the same time the improvement of the image processing technology also promote the progress of the particle detection.At present domestic particle detection technology falls behind of the foreign related technology, with the reason that the domestic solid particle detection technology research is not in-depth as the foreign, as well as the gas particles (bubble) detection. So that, the research for the detection technology of particle size distribution, especially the detection technology of gas particle is of great significance.The detection technology of particle size distribution, especially the detection technology of gas particle is studied in this paper, which is combined with the optical scattering method and image processing technology. The research in this paper mainly focuses on the detection technology of solid particle. Some of the related theory and data processing method of the technology is discussed to be used in the detection technology of gas particle. The main contents of the paper are as following:(a) The general situation of particle detection technology has been introduced. This paper puts forward that the solid particle detection technology can be used in gas particle detection, which can be used to improve the current fiber strength testing technology in the field of domestic textile industry. So that production process will be optimized, as well as the cost will be saved.(b) Some of the basic theory of light scattering is introduced as the theoretical basis of particle detection technology, such as Light extinction, Mie scattering theory, Fraunhofer diffraction, and laser holography method. According to the actual experiment, Mie scattering theory is chosen as the theoretical basis of the experiment. The Mie scattering theory is introduced in detail. The numerical solution formula is deduced. Following the formula, the simulation of the Mie scattering theory can be got with the Matlab. In hypothetical experimental conditions, the simulation of light signal which is received can be calculated theoretically, and the theoretical basis of the following experiment can be got, as well as the experimental accuracy judgment.(c) The theoretical basis of inversion algorithm is discussed. The basic theory of inversion is introduced, as well as the inversion calculation process. Constraints algorithm and unrestrained algorithm are introduced. According to the condition and purpose of the experiment, unrestrained algorithm is chosen as the inversion algorithm. The inversion calculation process of unrestrained algorithm is discussed, as well as Chahine algorithm, which is one of the classical unrestrained algorithms. Light signal coefficient matrix is calculated as the theoretical basis and inversion algorithmic fundamental of the data processing(d) This paper analyses the distribution and the motion state of particles in the liquid. The optical scattering correlation problem of the particles is discussed. It is determined that the scattered light produced by samples in the experiment is a correlation scattering. The state of motion of the particles in the liquid is introduced, and the mathematical model of particle swarm is established.(e) The particle size distribution testing technology based on the Mie scattering theory is studied in this paper. A set of experimental apparatus used for testing particle size distribution is set up. The optical structure of the apparatus is introduced, as well as experimental testing process. The method which is used to reduce the influence transmitted light signal is discussed. According to the five experiments with different subjects, the effectiveness and accuracy of the particle size distribution detection system are verified. The experimental results show that the measurement system can be effective for particle size distribution test. The experimental result shows the feasibility and effectiveness of the method which is proposed to improve spinning fiber strength testing process. According to the research work, a bubble detector is developed successfully.