非规则颗粒系统辐射特性分析
毕业论文关键词 非规则颗粒 时域有限差分法 （FDTD) 吸收因子 散射因子 吸收率 反射率
Title The radiation characteristics of irregular particle analysis
AbstractIn this paper, the finite difference time domain (FDTD) method was adopted, theradiation characteristics of irregular particle system analysed and studied.Respectively study the shape and scale parameters and the surrounding medium forsingle particle absorption factor and scattering factor influence. Found thatdifferent shapes of particles, in the direction of the incident light absorptioncross section, the greater the absorb scattering factor is larger; Particle sizeenough hours, due to the small size effect, absorption scattering factor in a localpeak; Around the medium the refractive index is different, its absorptionscattering factor is different also. In addition to an array of silvernanoparticles is calculated analysis, both the independent and the particlescattering independently, particle shape, concentration and particle scatteringis the change of the surrounding media, analyzes the change laws of reflectanceand absorption. Conclusion is independent scattering and absorption ability isstronger than scattering; Particle system in the influence of particle shapeabsorption rate reflectivity is not very big; The bigger the particleconcentration, the greater the absorptivity reflectance; Particle system indifferent medium, different radiation characteristics;
Keywords Irregular particle model Finite-difference time-domain(FDTD)Absorption factor Scattering factor Absorptivity Refractivity
目次
1引言1
1.1研究背景及意义1
1.3本文研究内容3
2颗粒辐射特性研究理论方法4
2.1常用的理论方法简介4
2.2时域有限差分方法简介5
2.3本章小结.7
3单个粒子的辐射特性影响因素分析.8
3.1FDTD模型的建立.8
3.2颗粒形状的影响9
3.3颗粒尺度参数的影响12
3.4颗粒周围介质的影响13
3.5本章小结.15
4粒子系的辐射特性影响因素分析.16
4.1FDTD仿真模型的建立16
4.2独立散射与非独立散射粒子系.17
4.3系统内粒子形状的影响.18
4.4系统颗粒周围介质的影响.19
4.5系统颗粒浓度的影响20
4.6本章小结.22
结论23
致谢24
参考文献.25
1 引言1.1 研究背景及意义自然界中有很多非规则颗粒，如近来经常出现的沙尘暴、冬季大范围的浓雾，很多加工物，例如煤炭、催化剂、水泥等大多数都是颗粒状且处于不规则状态 6。从二十世纪八十年代以来，为了满足科学研究与生产实践的需要，光散射法颗粒测量技术程度有了飞速的提升。例如近几年来，环境质量已经受到了人们愈加重视，所以对于环境质量监测与影响研究显得尤为重要，尤其是 PM2.5颗粒，国内外专家学者都在大力研究。研究粒子有很多重要的方面，辐射特性就是此中之一，通过对散射光的分析研究可以获得它的粒径、形状、浓度、折射率等相关信息。因此，在非规则粒子系统方面的辐射特性有很大的研究价值。热能传递有三种方式：热传导、热对流和热辐射。在传热学方面，对于辐射的研究一直都是重中之重。自然界中各个物体本身不仅能向其他物体发出热辐射，也能不断地从其他物体里吸收热辐射，辐射传热所关心的是由于物质的电磁运动所引起的热能传递