Migration of a charged sphere at an arbitrary velocity in an axial electric field
Migration of a charged sphere at an arbitrary velocity in an axial electric field
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DOI：
10.1016/j.colsurfa.2011.09.009
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发表时间：
2011-10
期刊：
影响因子：
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通讯作者：
S. Bhattacharyya;Partha P. Gopmandal
中科院分区：
文献类型：
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作者：
S. Bhattacharyya;Partha P. Gopmandal
本文研究了电解质溶液中胶体粒子在外加电场作用下的迁移。考虑了粒子沿电场方向以电泳速度或高于电泳速度的速度沿着平移的情况。通过求解Navier-Stokes方程、Nernst-Planck方程和Poisson方程，计算了粒子的非线性电动运动和受力。数值计算采用基于压力修正的迭代算法。分析了Navier-Stokes方程中的非线性惯性项对加速层极化和粒子附近离子分布的影响。研究了颗粒在几种流动条件下所受的水动力阻力和静电力的关系。结果表明，随着粒子速度从电泳速度上升，流体阻力逐渐接近斯托克斯阻力，电场力逐渐减小。在大的平移速度的粒子，粒子周围的净电荷分布是由扩散和平流机制。
In this paper we have studied the migration of a colloidal particle under the influence of an external electric field in an electrolyte solution. Situations in which the particle translates along the direction of the imposed electric field with electrophoretic velocity as well as at a velocity higher than that, is considered. The nonlinear electrokinetic motion and forces experienced by the particle is evaluated through solving the Navier–Stokes, Nernst–Planck and Poisson equations. A pressure correction based iterative algorithm is adopted for the numerical computations. The effect of nonlinear inertial terms in Navier–Stokes equations on the polarization of the EDL and ion distribution near the particle is analyzed. The dependence of hydrodynamic drag and electrostatic force experienced by the particle under several flow conditions is studied. Our results show that as the particle velocity rises from its electrophoretic velocity, the hydrodynamic drag gradually approaches the Stokes drag and the electric force diminishes. At large translational speed of the particle, the net charge distribution around the particle is governed by both diffusion and advection mechanisms.