中文摘要：

对烟颗粒的光散射进行模拟计算是研究火灾烟颗粒光散射特性的重要手段,目前对于火灾烟颗粒光散射的数值计算多采用球形或椭球模型.实际上,火灾烟颗粒的形貌与球形和椭球均存在着显著差异.扫描电子显微镜图像表明,烟颗粒具有近似分形的结构.本文利用离散偶极近似方法计算了随机取向的火灾烟颗粒分形凝团以及同体积的球形颗粒的光散射Muller矩阵,并对两者的归一化Muller矩阵元素随散射角的分布进行了比较.研究表明：火灾烟颗粒分形模型和球形模型的归一化矩阵元素F11（θ）/F11（0）,F22（θ）/F11（θ）和F34（θ）/F11（θ）随散射角的分布情况存在显著差异;利用两种模型的光散射矩阵元素F22（θ）/F11（θ）的差异,可以有效区分烟颗粒与球形干扰颗粒。

英文摘要：

It is important to research light scattering from fire smoke particles by numerical calculation.Traditionally,spherical or spheroid models were used to approximate the shape of smoke particles for light scattering calculations.But actually,smoke particles have a similar fractal structure,which is different from spherical structure.Using the discrete-dipole approximation method,the light scattering Muller matrices were computed for the randomly oriented fractal aggregate,as well as the spherical particle with the same aggregate volume,and then their normalized Muller matrix elements were compared.The results indicate that the angular distributions of the normalized matrix elements F11（θ） /F11（0）,F22（θ） /F11（θ） and F34（θ） /F11（θ） have significant differences between the fractal model and spherical model.We can discriminate spherical non-fire aerosols from smoke particles,using the difference of F22（θ） /F11（θ） between fractal model and spherical model.