Effect of Discharge Electrode Parameters on the Flow Velocity Profile of the Wire-rod Type Electrohydrodynamic Gas Pump Exit

Experimental investigation has been conducted to study the effects of corona wire diameter, pipe length, and corona polarity on outlet flow velocity distribution profile of a wire-rod type electrohydrodynamic (EHD) gas pump. Upon applying negative or positive dc high voltage between a wire electrode (outer diameter (o.d.) 60 mum, 200 mum, or 300 mum) and a rod electrode (o.d. 3 mm) in atmospheric air, corona discharge occurs and EHD gas flow is generated in the direction from the wire electrode to the rod electrode through a cylindrical pipe (inner diameter (i.d.) 20 mm). For both polarities, the discharge current and average flow velocity increase monotonically on increasing the applied voltage before the onset of spark discharge. Using wire electrodes with a smaller diameter, stable corona discharge between corona onset and spark onset is generated in a wider voltage range, and the discharge current becomes larger, resulting in a higher flow velocity. The maximum average flow velocity of 2.0 m/s, corresponding to a flow rate of 38 1/min, was achieved with a wire of diameter 60 mum by applying a voltage of -16 kV.