Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Thermal Engineering, Tsinghua University, Beijing 100084, China.
J Colloid Interface Sci. 2010 Apr 1;344(1):214-20. doi: 10.1016/j.jcis.2009.12.050. Epub 2009 Dec 28.
Advective flow of a permeable sphere in an electrical field is comprehensively studied. The sphere has a uniform permeability and is subject to an incoming Newtonian flow. The electrical field generates an electro-osmotic flow inside the sphere, which markedly affects sphere flow dynamics. A numerical model elucidates the effects of flow dynamic parameters on the drag coefficient and ratio of drag forces to a permeable and solid sphere. The model solves the Navier-Stokes equations both inside and outside the porous sphere. The unique flow field and pressure patterns of the permeable sphere flow are characterized in detail, and utilized to interpret the distinguishing flow behaviors of spheres induced by electro-osmotic flow. Drag force decreases and or reverses in direction when the intensity of the electro-osmotic flow in the sphere increases. When the electro-osmotic flow is counter to the incoming flow, drag force increases significantly, and vortices form near the sphere. As the sphere becomes highly permeable, the influence of the electro-osmotic flow and incoming flow velocity are reduced markedly.
对可渗透球体在电场中的平流运动进行了全面研究。球体具有均匀的渗透性，受到牛顿流入流的影响。电场在球体内产生电动流，这显著影响球体流动动力学。数值模型阐明了流动动力学参数对阻力系数和可渗透球体与固体球体之间阻力比的影响。该模型在多孔球体内部和外部求解纳维-斯托克斯方程。详细描述了可渗透球体流动的独特流场和压力模式，并利用其解释电渗流引起的球体的区别流动行为。当球体内的电渗流强度增加时，阻力减小或方向反转。当电渗流与流入流相反时，阻力显著增加，并且在球体附近形成涡旋。当球体变得高度可渗透时，电渗流和流入速度的影响明显减小。
