Effect of Electrode Arrangements on EHD Conduction Pumping

An experimental investigation is conducted to develop an electrohydrodynamic (EHD) pump based on microelectromechanical systems technology. In EHD conduction pumping, Coulomb force is the main driving force for fluid motion. The nonequilibrium process of the dissociation and recombination of dielectric liquid, HFE-7100, produces heterocharge layers in the vicinity of the electrodes. The attraction between the heterocharge layers and electrode surfaces generates the net motion in the dielectric liquid by applying asymmetric electric fields. In order to generate the asymmetric electric fields, three electrode patterns were prepared. The working fluid was confined between two electrodes facing each other. The generated pressure was measured for the different asymmetric electric fields. Also, the effect of deviation between the upper and lower electrode patterns on the pressure was investigated. Finally, the liquid flow rate, power consumption, and pump efficiency were measured with an optimized electrode arrangement. It is clear from the experimental results that, in addition to the conduction pumping, the ion injection generated at the microelectrode edge increases the pressure.