Effect of electrode arrangements on EHD conduction pumping

An experimental investigation is conducted to develop an electrohydrodynamic (EHD) pump based on micro-electro-mechanical systems (MEMS) technology. In EHD conduction pumping, Coulomb force is the main driving force for fluid motion. The non-equilibrium process of dissociation and recombination of dielectric liquid, HFE-7100, produces hetero-charge layers in vicinity of electrodes. The attraction between the hetero-charge layers and electrode surfaces generate 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 the two electrodes which face each other. The generated pressure and the liquid flow rate were measured for the different asymmetric electric fields. Also, the alignment between the upper and the lower electrode patterns on the pressure was investigated. It is cleared from the experimental results that, in addition to the conduction pumping, the ion injection generated at the micro-electrode edge increase the pressure.