Impact of necking and overlapping on radiative properties of coated soot aggregates
Impact of necking and overlapping on radiative properties of coated soot aggregates
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DOI：
10.1080/02786826.2016.1275513
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发表时间：
2017-01
影响因子：
5.2
通讯作者：
N. Doner;Fengshan Liu;J. Yon
中科院分区：
文献类型：
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作者：
N. Doner;Fengshan Liu;J. Yon
摘要采用离散偶极子近似（DDA）数值研究了颈缩和重叠对涂覆烟尘聚集体辐射特性的影响。本研究关注初级粒子之间的轻微重叠和小到中等颈缩的情况。研究了重叠、颈缩和涂层对骨料体积等效半径的影响。为了显示重叠效应，在可见和近红外四个不同波长下，对N = 200个粒子组成的聚集体在有涂层和没有涂层的情况下的辐射特性进行了评估，其中烟灰核心的折射率为m = 1.60 + 0.60i，涂层材料的折射率为m = 1.46。以0.05、0.1、0.2三个交叠值对涂覆烟尘聚集体的辐射特性进行了计算。此外，在0.05、0.1和0.2的重叠值下，未包覆的聚集体和25%、50%、75%和100%包覆的聚集体的吸收截面与波长之间的关系得到了说明。随着重叠和颈缩的增加，计算出的消光、吸收和散射特性在可见光和近红外区域也增加了。当颈缩值为0.40 ~ 0.50时，包覆骨料的体积等效半径随包覆厚度呈线性增加。版权所有©2017美国气溶胶研究协会
ABSTRACT The impact of necking and overlapping on the radiative properties of coated soot aggregates was investigated numerically by using the Discrete Dipole Approximation (DDA). The present study concerns the situations of slight overlapping between primary particles and small to moderate necking. The effects of overlapping, necking, and coating on the aggregate volume equivalent radius were presented. To show the overlapping effect, the radiative properties of aggregates consisting of N = 200 particles were evaluated with and without coating at refractive indices of m = 1.60 + 0.60i for the soot core and m = 1.46 for the coating material at four different wavelengths in the visible and near-infrared. The radiative properties of coated soot aggregates with three overlapping values of 0.05, 0.1, and 0.2 were calculated. In addition, the relationship between absorption cross-section and wavelength was illustrated at overlapping values of 0.05, 0.1, and 0.2 for uncoated and 25%, 50%, 75%, and 100% coated aggregates. As overlapping and necking increased, the calculated extinction, absorption, and scattering properties also increased in the visible and near-infrared regions. It was found that the volume equivalent radii of coated aggregates increased linearly with coating thickness when the necking values were 0.40–0.50. Copyright © 2017 American Association for Aerosol Research