Theoretical/numerical study of electrohydrodynamic pumping through pure conduction phenomenon

In an isothermal liquid, only the Coulomb force which is the force acting on the free charges, can contribute to net electrohydrodynamic (EHD) motion. In the absence of a direct charge injection or induction, the charges can be generated through the dissociation process of the fluid. The generated charges by dissociation are redistributed by the applied electric field, resulting in the heterocharge layers around the electrodes. The pumping of an isothermal liquid without ion injection is associated with the heterocharge layers of finite thickness in the vicinity of the electrodes. This type of pumping is referred to as the conduction pumping. This paper investigates the conduction pumping mechanism theoretically through the numerical solutions. For this purpose, a theoretical model for the static case (i.e., without a flow motion) is established and a numerical code using the finite volume method is developed. Electric potential, electric field, charge density and electric body force distributions for the selected electrodes configuration are presented. The generated pressure as a function of applied voltage is also presented. The numerical results confirmed the EHD conduction pumping concept theoretically.