孔隙率对气溶胶凝聚粒子光学特性的影响

Effect of Porosity on Optical Properties of Aerosol Aggregate Particles

采用Monte-Carlo方法,对气溶胶凝聚粒子进行了模拟,讨论了凝聚粒子的孔隙特性,分析了空间结构、原始粒子数目对凝聚粒子孔隙率和等效折射率的影响。结合物质的电结构,将气溶胶凝聚粒子离散为一系列偶极子,利用离散偶极子近似方法,数值计算了不同孔隙率气溶胶凝聚粒子的散射、吸收和消光截面各种取向的统计平均值。结果表明,气溶胶凝聚粒子的孔隙率明显取决于其空间形状和所含原始微粒的数目;气溶胶凝聚粒子的等效折射率、吸收、散射和消光截面则随孔隙率的增加而减小。研究结果可为全面理解气溶胶粒子光学特性提供参考;也可为某些涂层材料光学性能的改变提供参考,通过改变涂层材料中凝聚粒子的孔隙率来改变涂层材料的等效折射率,进而改变涂层材料对光的散射和吸收。

Taking Monte-Carlo method to simulate the aerosol aggregate particles and discussing the porosity characteristics of aggregate particles,the effects of spatial shape and number of original particles on the porosity and effective refractive index of aggregate particles are analyzed.According to the electrical structures of substance,the aerosol aggregates particle are dispersed into a series of dipoles,and by discrete dipole approximation method,the statistical average values of scattering,absorption and extinction cross sections of aerosol aggregate particles with different porosities are obtained.The results show that the porosity of aerosol aggregate particles significantly depends on the spatial shape and number of original particles of aerosol aggregate particles.The effective refractive index,absorption,scattering and extinction cross section decrease with the porosity increasing.The findings can provide a reference for a comprehensive understanding of the optical properties of aerosol particles,and for the optical property of some coating materials by changing the porosity of aggregate particles in the coating material.This affects the effective refractive index of the coating material so that the light scattering and absorption of the coating material are changed.