Kadaksham Arun T J, Singh Pushpendra, Aubry Nadine
Department of Mechanical Engineering, New Jersey Institute of Technology, University Heights, Newark, NJ 07102, USA.
Electrophoresis. 2004 Nov;25(21-22):3625-32. doi: 10.1002/elps.200406092.
A numerical scheme based on the distributed Lagrange multiplier method (DLM) is used to study the motion of nano-sized particles of dielectric suspensions subjected to uniform and nonuniform electric fields. Particles are subjected to both electrostatic and hydrodynamic forces, as well as Brownian motion. The results of the simulations presented in this paper show that uniform electric fields the evolution of the particle structures depends on the ratio of electrostatic particle-particle interactions and Brownian forces. When this ratio is of the order of 100 or greater, particles form stable chains and columns, whereas when it is of the order of 10 or smaller the particle distribution is random. For the nonuniform electric field cases considered in this paper, the relative magnitude of Brownian forces is in the range such that it does not influence the eventual collection of particles by dielectrophoresis and the particular locations where the particles are collected. However, Brownian motion is observed to influence the transient particle trajectories. The deviation of the particle trajectories compared to those determined by the electrostatic and hydrodynamic forces alone is characterized by the ratio of Brownian and dielectrophoretic forces.
一种基于分布式拉格朗日乘数法（DLM）的数值方案被用于研究处于均匀和非均匀电场中的介电悬浮液纳米级颗粒的运动。颗粒受到静电力、流体动力以及布朗运动的作用。本文给出的模拟结果表明，在均匀电场中，颗粒结构的演变取决于静电颗粒间相互作用与布朗力的比值。当该比值为100或更大时，颗粒形成稳定的链和柱，而当它为10或更小时，颗粒分布是随机的。对于本文所考虑的非均匀电场情况，布朗力的相对大小处于这样一个范围内，即它不会影响最终通过介电泳对颗粒的收集以及颗粒被收集的特定位置。然而，观察到布朗运动会影响颗粒的瞬态轨迹。与仅由静电力和流体动力确定的轨迹相比，颗粒轨迹的偏差由布朗力与介电泳力的比值来表征。
