Numerical study of micro-scale EHD conduction pumping: The effect of pump orientation and flow inertia on heterocharge layer morphology and flow distribution control

Abstract

Innovative technological solutions for thermal management of components at small scales, such as electrohydrodynamic (EHD) conduction pumping, are being developed to enable the next generation of miniaturized high density electronics. In EHD conduction, a strong electric field is applied via asymmetric submerged electrodes in a dielectric liquid. The field enhances the dissociation of electrolytic impurities present within the fluid, generating ions that migrate to form heterocharge layers over each electrode. The subsequent abundance of asymmetrically distributed space charge generates a net Coulomb force that is applied on the fluid, producing a net flow in the direction of the force. EHD conduction pumps have no moving parts, consume very little power, and have simple, flexible designs that can be easily miniaturized to the micro-scale. This study numerically investigates the heterocharge layer morphology of EHD conduction pumping used in flow distribution control between parallel micro-scale branches, using different pumping orientations and accounting for flow inertia effects. The results are qualitatively compared with available experimental data and serve to explain observed behaviors.