A systematic investigation on flow characteristics of needle-ring-net electrohydrodynamic gas pump

Abstract

In this study, a two-dimensional numerical simulation is conducted to investigate the characteristics of gas flow induced by an electrohydrodynamic (EHD) pump with needle-ring-net electrodes. A needle electrode and a ring electrode are used as the high-voltage electrode, and a net electrode is used as the grounding one. The electric field distribution, space charge distribution and flow field distribution behavior were simulated and analyzed in detail. The simulation results were in good agreement with experimentally measured data. The influence of key parameters including applied voltage, electrode configurations and channel diameter on the flow characteristics and energy efficiency of EHD pump were studied systematically. The results showed that the most pronounced electric field strength locates at region around the needle tip and the edge of the ring electrode, while there is not obvious evidence showing more space charge located at vicinity of ring electrode. The airflow velocity at the net pores is higher than that at the central circular hole. Flow velocity and energy conversion efficiency of the pump monotonically increases with applied voltage. A combinational effect of tip-ring distance, ring inner diameter and pump channel size should be considered to design the EHD pump to achieve a maximum efficiency. The results also showed that an optimal energy conversion efficiency of 4.26 % can be achieved which is higher than most of the other EHD pumps (0.11~2.56 %). The proposed model can serve as an efficient tool for the design and optimization of the needle-ring-net EHD gas pumps.