The Particle Size Measurement Spectrum Light Extinction Of The Particle Dispersion

With the growing development and improvement of science and technology and production process, the particle size is continuously decreasing. In the scientific research and industrial and agricultural production, rapid and accurate monitoring of the particle concentration and distribution has very important significance to improve product quality, reduce energy consumption, control environmental pollution, and protect human health.This paper introduces the principle and method of spectral extinction measurement of small particle. In the visible light region, the influence of the refractive index of particles, size parameters, and the incident light on the extinction properties of particles was systematically analyzed. Based on the dispersion relation of the refractive index of particle, we analyze the spectral extinction properties of a certain particle size distribution. The results show that the influence of small varied dispersion relation of particles(water, glass beads) on the spectral extinction properties can be neglected; while the obvious varied dispersion relation of particles has greater impact on the spectral extinction properties.Optical properties of some small particles are different from the bulk material. This paper presents a measurement method of the dispersion relation of particles. We measured the refractive index of tear gas smoke particle at three different wavelengths based on the Air theory of the laser rainbow of small particles. The dispersion relation was obtained by using Sellmeier equations. The results show that tear gas smoke particles have strong dispersion properties. Based on the dispersion relation of the smoke particles, the concentration and size distribution of the tear gas smoke particles generated by the laboratory were measured by using spectral extinction measurement system.The theoretical analysis and experimental results show that, size measurement accuracy of strong dispersive particles can be improved by using the spectral extinction method based on the dispersion relation of particles. It provides a theoretical basis for rapid and accurate monitoring of the particle concentration and size distribution.