Electrohydrodynamic Gas Pump in a Vertical Tube

The characteristics of an electrohydrodynamic (EHD) gas pump were experimentally evaluated in this study. Experiments were conducted using positive DC voltage (13.0 kV – 30.0 kV), applied to a thin corona wire of diameter 0.51 mm. The ground plate used in the study was mounted on the inner surface of a cylinder and had a width of 12.7 mm and a total exposed surface area of 1.52 × 10⁻³ m². The pumps tested were identical except for their spacing between the emitting electrode and the ground plate, which varied from 0.66D to 1.33D. The results show that the current on the ground plate increases as the applied voltage increases. It is also observed that the applied voltage at which flow was first detected in the cylinder correlates well with the electrode spacing. It appears that the four electrodes placed along the surface of the pipe were able to disturb the boundary layer enough to create a uniform flow profile within the pipe. As a result, flow as high as 2.5 m/s was observed in the cylinder with an electrode spacing of L/D = 1.33. The results also show that the ionic wind velocity increases with an increasing EHD Reynolds number for L/D = 0.66 and 1.0, but decreases with the EHD Reynolds number for L/D > 1.