Transient Heterocharge Layers Development in EHD Conduction Pumping

Electrohydrodynamic conduction pumping uses the interaction between a strong, externally applied electric field and dissociated electrolyte impurities within a dielectric working fluid to generate fluid motion. Such a strong electric field applied to submerged electrodes causes the formation of ionic layers over the electrodes, referred to as heterocharge layers. These layers produce significant regions of space charge, which translate to the presence of opposing Coulomb forces on the ions in the fluid [1]. The magnitude of this force derives from the morphology and charge concentration of these layers and how they form with time. While the shapes of heterocharge layers at steady state pumping conditions have been studied, the transient growth and morphology have not been explored. This paper numerically investigates the transient growth and resultant charge concentration of heterocharge layers of EHD conduction pumping within a liquid channel in the presence of a prescribed inlet velocity. Additionally, the transient liquid flow fields near the electrodes are also presented.