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

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 behaviors were simulated and analyzed in detail. The simulation results were in good agreement with the experimentally measured data. The influence of key parameters, including applied voltage, electrode configurations, and channel diameter, on the flow characteristics and energy efficiency of an EHD pump was studied systematically. The results showed that the most pronounced electric field strength locates at the region around the needle tip and the edge of the ring electrode, while there is no obvious evidence showing more space charge located at the vicinity of the 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 increase 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 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.