Micro-Electrohydrodynamic Pump by Dielectric Fluid

A Micro-Electrohydrodynamic (EHD) pump is tested experimentally. The EHD pump examined in this paper is fabricated with two cylindrical copper electrodes of the inner diameter 3mm. The distance between electrodes was changed from 0.6mm to 1.2mm. In order to simplify the characterization of the pressure capacity of the EHD pump, the uniform electric field added in the gap between the cylindrical electrodes using aluminum disc electrodes (40mm outer diameter). The static pressure and the mean velocity in a closed fluidic circuit were measured with Dibutyl sebacate as working fluid. The liquid has a dielectric constant, ε/ε_0=4.8 and a low electric conductivity, σ=4.7×10^<-10> (S/m). The static pressure results are compared with the theoretical results. The theoretical model is based on the unipolar conduction which generates the space charge in the liquid. In this model, the Coulomb force can contribute to the EHD motion. The static pressure results show a linear relationship with the square of the electric filed. This linear relationship supports the assumption that the unipolar conduction generates the pressure driving force. The estimation of the EHD pump efficiency based on the theoretical model is 18% with the electrode gap of 1.2mm between the electrodes and 5% with the one of 0.6mm.