Influence of Electrode Spacing on a Symmetrical Washer-Type Electrohydrodynamic Conduction Pump

Abstract

Electrohydrodynamic (EHD) pumping is an attractive method that can be applied to drive a fluid in mass transport and heat transfer enhancement applications, and more particularly for microfluidic applications. EHD pumps are very interesting because they do not require moving parts. The electric energy is directly converted into kinetic energy via the Coulomb force. Three modes can generate this fluid motion: conduction, induction, and injection. This paper presents the experimental results of a parametric investigation on EHD conduction pumps with washer-type electrode geometry. Only symmetrical electrode configuration is investigated in order to highlight the influence of the positive/negative charge mobility ratio. The working fluid is a dielectric liquid (HFE-7100). The pumping mechanism is examined with several washer-type electrode geometries and different types of spacers. For each configuration, pressure and current time variations are recorded and compared.