Affiliation: | aDepartment of Chemical Engineering, National Taiwan University, Taipei 10617, Taiwan bDepartment of Mathematics, Tamkang University, Tamsui, Taipei 25137, Taiwan cDepartment of Mechanical Engineering & Fuel Cells Research Center, Yuan Ze University, 135 Yuan-Tung Road, Chung Li, Tao Yuan 320, Taiwan dDepartment of Mathematics, Tunghai University, Taichung 403, Taiwan |
Abstract: | The electrokinetic flow of an electrolyte solution in an elliptical microchannel covered by an ion-penetrable, charged membrane layer is examined theoretically. The present analysis extends previous results in that a two-dimensional problem is considered, and the system under consideration simulates the flow of a fluid, for example, in a microchannel of biological nature such as vein. The electroosmostic volumetric flow rate, the total electric current, the streaming potential, and the electroviscous effect of the system under consideration are evaluated. We show that, for a constant hydraulic diameter, the variations of these quantities as a function of the aspect ratio of a microchannel may have a local minimum or a local maximum at a medium level of ionic strength, which depends on the thickness of the membrane layer. For a constant cross-sectional area, the electroosmostic volumetric flow rate, the total electric current, and the streaming potential increase monotonically with the increase in the aspect ratio, but the reverse is true for the electroviscous effect. |