基于米氏散射理论的水中悬浮颗粒物散射特性计算

Study on Properties of Light Scattering Based on Mie Scattering Theory for Suspended Particles in Water

降低或减少水体中悬浮颗粒物的光散射影响是直接光谱法检测水质化学需氧量（COD）的关键技术问题。为此,依据米氏散射理论,采用改进型连分式结合后向递推算法,研究了紫外-可见光照射下水体中藻类和泥沙类悬浮颗粒物的光散射特性。通过构造球形粒子的光散射模型,在入射光波波长为200~1000 nm、悬浮颗粒物尺寸为1~200μm的条件下,分析和计算了散射光强度和角度的变化规律。仿真结果表明：当改变粒子尺寸,调节入射光波长时,两种悬浮颗粒物的散射光强与散射角度呈现显著变化,这为进一步提高基于紫外-可见吸收光谱法的水质检测精度和降低散射影响提供了依据。

Reducing or decreasing light scattering effects of suspended particles in water is one of the key technical issues of the direct spectroscopy chemical oxygen demand （COD） water quality detection. Therefore, based on the Mie scattering theory, the improved continued fractions combining with backward recursion algorithm is used to study ultraviolet （UV）-visible light scattering properties on the alga and sand suspended particles in water. The light scattering models of spherical particles in water is built. The changes of light scattering intensity and scattering angle are analyzed and calculated with particle size in the range of 1-200 ~tm and the incident wavelength in the range of 200-1000 nm. The simulation results show that when the particle size and the wavelength of incident light change, the scattered light intensity and angle are significantly changed with two types of suspended particles. It is helpful to improve resolution and degrade the effect of scattering of detection of water quality using UV-visible absorption spectroscopy.