Orientation effects on near-field radiative heat transfer between complex-shaped dielectric particles
Orientation effects on near-field radiative heat transfer between complex-shaped dielectric particles
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DOI：
10.1063/5.0116828
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发表时间：
2022-07
影响因子：
4
通讯作者：
Lindsay P. Walter;M. Francoeur
中科院分区：
文献类型：
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作者：
Lindsay P. Walter;M. Francoeur
介绍了取向对两个形状复杂的SiO2超椭球粒子之间近场辐射传热的影响。所研究的颗粒半径为50 nm，粒径可变。取向的特点是在两个粒子系统的旋转对称的程度，和辐射电导计算使用离散系统绿色的函数方法来考虑所有的电磁相互作用。结果表明，在某些取向的总电导可以高达其他取向的两倍时，颗粒的质心间距为110 nm。取向效应与系统的旋转对称性并不显著相关，但与粒子之间的最小真空间隙距离密切相关。因此，近场辐射热传递的取向效应是颗粒拓扑结构的结果，更极端的拓扑结构导致在更大的颗粒质心分离距离处的取向效应的延续。凹超椭球体颗粒显示出显著的取向效应，直到质量中心分离距离约等于颗粒半径的3.9倍，而凸超椭球体颗粒显示出显著的取向效应，直到质量中心分离距离约等于颗粒半径的3.2倍。与以前的各向异性，球形偶极子的研究，这些结果的复杂形状的超椭球体颗粒表明，方向的影响变得可以忽略不计时，热传递是一个体积的过程中的所有方向。这项工作是必不可少的了解粒子之间的辐射传输，具有不规则的几何形状或可能有几何缺陷或异常。
The effect of orientation on near-field radiative heat transfer between two complex-shaped superellipsoid particles of SiO2 is presented. The particles under study are 50 nm in radius and of variable concavity. Orientation is characterized by the degree of rotational symmetry in the two-particle systems, and the radiative conductance is calculated using the discrete system Green's function approach to account for all electromagnetic interactions. The results reveal that the total conductance in some orientations can be up to twice that of other orientations when particles are at a center-of-mass separation distance of 110 nm. Orientation effects are not significantly correlated with system rotational symmetries but are strongly correlated with the minimum vacuum gap distance between particles. As such, orientation effects on near-field radiative heat transfer are a consequence of particle topology, with more extreme topologies leading to a continuation of orientation effects at larger particle center-of-mass separation distances. The concave superellipsoid particles display significant orientation effects up to a center-of-mass separation distance approximately equal to 3.9 times the particle radius, while the convex superellipsoid particles display significant orientation effects up to a center-of-mass separation distance approximately equal to 3.2 times the particle radius. In contrast to previous anisotropic, spheroidal dipole studies, these results of complex-shaped superellipsoid particles suggest that orientation effects become negligible when heat transfer is a volumetric process for all orientations. This work is essential for understanding radiative transport between particles that have non-regular geometries or that may have geometrical defects or abnormalities.