一种基于Mie散射的颗粒物浓度测量方法

 根据Mie 散射理论，采用连分式递推算法，进行了微粒散射的数值模拟。借助特殊函数库得出简化的Mie 散射理论的数值模拟方法，省去了推导的复杂性，同时提高了计算程序运算速度。利用水溶胶模拟大气溶胶进行光散射实验，采用三波长法计算得到各样本的平均粒径，根据消光定律模拟出微粒浓度与光强变化之间的关系，为空气中微粒浓度的测量提供了理论依据。

A Method for Measuring Particle Concentration Based on Mie Scattering

Numerical simulation of particle scattering was realized using the continued fraction recursion method based on Mie scattering theory. An easy numerical simulation method was obtained by the aid of special function library in the Mie scattering theory, improving the computing speed. The extinction coefficient was obtained by numerical simulation with a different refractive index variation of particle diameters. The result revealed that light scattering effects of particles with different refractive index were similar to those of water and dust, when the particles' diameter is larger than a certain value. The light scattering experiment of aerosols in the atmosphere was simulated using hydrosol, while the dust samples collected in different areas were used as particles. Light scattering data of the dust sample at different wavelengths and different concentrations were obtained and compared with those of SiO₂ particles whose diameter is 400 nm. Three wavelength method was used to obtain an average particle size of the sample, which is verified by SiO₂ particles' experiment results. Using the average particle sizes of each sample, the relationships between particle concentration and light intensity variation were simulated according to the law of extinction. The experimental results are consistent with those obtained theoretically. It provides a good theoretical basis for measuring the concentration of particles in the air.