Liquid pumping by miniature electrohydrodynamic pump driven by DC voltage

Abstract

In this paper the design and performance of the miniature electrohydrodynamic (EHD) pump driven by DC voltage is presented. The EHD pump had a pipe-like shape of the inner diameter of 0.5 mm with two concentric pipe electrodes. The EHD pump was powered by positive high DC voltage (up to 12 kV). When high voltage was applied the net flow of the working liquid was observed. Pumping tests were performed using isopropyl alcohol (CH <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> ) <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> CHOH as working liquid. The direction of the flow was from the grounded electrode toward the HV electrode. The flow rate and pressure generated by the EHD micropump was measured. The highest flow rate of 0.5 ml/min was obtained for 12 kV of applied voltage. The maximum measured pressure was 500 Pa for applied voltage of 6 kV. Further increasing of the applied voltage led to the formation of gas bubbles in the working liquid and subsequently the decrease in the pumping efficiency. The current-voltage characteristics was measured for open and closed outlet of the micropump. The maximal current of 20 μA was measured for the applied voltage of 12 kV and open outlet of the pump. This corresponds to the power consumption of 240 mW.