煤烟凝聚粒子的光散射特性研究

离散偶极子近似方法(Discrete Dipole Approximation,DDA)是研究粒子散射特性的重要理论方法之一.利用该方法研究了煤烟凝聚粒子的散射问题,讨论了分形煤烟凝聚粒子的散射强度随凝聚粒子的形状、结构、相对折射率及入射波波长变化的情况.结果表明:煤烟凝聚粒子的光散射特性与其形状有着非常密切的关系;对于一个给定的形状不变的煤烟凝聚粒子,它的散射强度的大小随着入射波波长的不同而发生变化;另外组成煤烟凝聚粒子的基本粒子的个数也会影响煤烟凝聚粒子的散射强度,组成煤烟凝聚粒子的基本粒子的半径比入射波的波长小得越多,煤烟凝聚粒子的散射强度就减小得越快.

Studies on Light Scattering Properties of Soot Aggregates

The discrete dipole approximation(DDA) is a flexible and powerful technique for computing scattering and absorption by targets of arbitrary geometry.This method was used to solve the soot aggregates scattering problem and the change of the scattered sensitivities of fractal-like soot aggregates with the changes of figure,construct,refractive index values,and the wavelength of incident wave was discussed.All these numerical results give out that the light-scattering properties of the soot aggregates strongly depend on the structure of the soot aggregates;the scattering intensity was different in different incident wavelength for a fixed structure;the scattering intensity was effected by the number of primary particles that constitute the soot aggregates,because the total intensity decreased quickly if the monomer radius is much smaller than the incident wave.