激光散射法悬浮颗粒浓度检测的理论研究

Theoretical Study on Concentration Monitoring of Suspended Particles by Laser Scattering Method

悬浮颗粒浓度是环境污染物浓度检测中一项重要指标。针对空气中悬浮颗粒浓度自动测量的实现方法问题,研究了一种基于激光散射法测量悬浮颗粒浓度的理论方法。确定了以Mie散射原理作为激光散射法测量颗粒浓度的理论依据。在Mie散射的基础上,对悬浮颗粒物的光散射特性进行了理论分析,通过MATLAB软件仿真分析了不同特征参数下的单个悬浮颗粒的散射光强度分布曲线和消光系数曲线,分别得到了散射光强分布与入射光波长λ、折射率m(实部和虚部)、颗粒粒径α之间的关系。结合仿真分析的结果,应用遗传寻优算法对粒径分布进行反演,通过反演结果证明了本方案在理论上的可靠性。验证表明,该研究所设计方法能精确地实现悬浮颗粒物质量浓度的测量,为相关检测仪器的设计提供理论基础。

Suspended particles detection is an important indicator of environmental pollution detection. Aiming at the measurement of suspended particles in the air,a theoretical design method is studied in this paper,which is based on the laser scattering method to measure the concentration of suspended particles. Firstly,the theory of particle concentration measurement based on laser scattering method is used for Mie scattering theory. Secondly,the light scattering properties of suspended particulate matter has been analysed,through the MATLAB simulation different characteristic parameters of a single suspended particle scattering light intensity distribution curve and extinction coefficient, get the relationship between the scattered light intensity distribution and the incident wavelength λ,the refractive index m（real part and imaginary part） and the particle size α. Finally,based on the simulation results,the particle size distribution is retrieved by the genetic algorithm,and the reliability of the scheme is proved by the inversion results. The verification shows that the method can accurately measure the mass concentration of suspended particulate matter.