Gorman Matthew, Ruan Xuan, Ni Rui
Department of Mechanical Engineering, Johns Hopkins University, Baltimore, Maryland 21218, USA.
Phys Rev E. 2024 Mar;109(3-1):034902. doi: 10.1103/PhysRevE.109.034902.
From colloid suspension to particle aggregation in protoplanetary formation, electrostatic attraction and repulsion between particles is a key mechanism behind the aggregation and clustering of particles. Although most studies have focused on canonical spherical particles, it remains unclear how nonspherical and rough dielectric particles interact and whether the complicated interplay between roughness and charge distribution affects their force couplings. Here a boundary-element method model was leveraged to study electrostatic interactions between charged dielectric particles with modular, axisymmetric surface features. Charge accumulation at convex surface asperities decreases the strength of electrostatic interactions between particles, and the sensitivity of the electrostatic force to the particle surface roughness and orientation is especially apparent at small particle separations. Surface interactions between the particle near-contact regions were isolated to determine the degree that near-contact interactions dictate the relationship between the net electrostatic force and the particle roughness and orientation. A correction factor ΔF is introduced to recover higher order dielectric effects from a low order analytical model. Finally, implications of surface charge asymmetries produced for different particle orientations and surface roughnesses on the long-standing problem of triboelectrification are discussed.
从原行星形成过程中的胶体悬浮到粒子聚集，粒子间的静电吸引和排斥是粒子聚集和聚类背后的关键机制。尽管大多数研究集中在标准球形粒子上，但尚不清楚非球形和粗糙介电粒子如何相互作用，以及粗糙度和电荷分布之间复杂的相互作用是否会影响它们的力耦合。在此，利用边界元方法模型研究具有模块化轴对称表面特征的带电介电粒子之间的静电相互作用。凸面粗糙度处的电荷积累会降低粒子间静电相互作用的强度，并且在小粒子间距下，静电力对粒子表面粗糙度和取向的敏感性尤为明显。隔离粒子近接触区域之间的表面相互作用，以确定近接触相互作用在多大程度上决定净静电力与粒子粗糙度和取向之间的关系。引入校正因子ΔF以从低阶解析模型中恢复高阶介电效应。最后，讨论了不同粒子取向和表面粗糙度产生的表面电荷不对称对长期存在的摩擦起电问题的影响。
