Polarity Effect and Flow Characteristics of Wire-Rod Type Electrohydrodynamic Gas Pump
The electrohydrodynamic (EHD) flow characteristics for a wire to rod type EHD gas pump have been experimentally investigated. Experiments were conducted for DC negative and positive applied high voltage to a corona wire of diameter 0.24 mm from 0-24 kV, grounding rod electrode diameter from 1.5 mm to 3.1 mm and wire/rod electrode distance to pipe diameter ratio from 0.63 to 1.16. It was observed that the polarity plays an important role, where a negative high voltage generates a higher gas flow than that of a positive polarity. The results show that a maximum of 40 L/min of gas flow rate is generated at 0.37 W energy input when the pipe diameter is 20 mm with the corona wire electrode and grounding rod electrode gap distant set to 12.6 mm under negative applied voltage compared to 25 L/min at 0.23 W energy input for the positive case at the same specific energy density.
An EHD Gas Pump Utilizing a Wet Porous Point Electrode
A point-to-mesh type electrohydrodynamic (EHD) gas pump, utilizing a wet porous point electrode, has been proposed, and the effect of the wet porous point electrode on the gas flow velocity and flow generation yield of the EHD gas pump was investigated. The wet porous point is used as a corona discharge electrode, and the mesh is used as an ion collecting electrode. It was observed that the EHD gas pump with the wet porous point electrode can generate a higher gas flow velocity and flow generation yield than the same design EHD gas pump with a non-porous metal point electrode. As a result with the wet porous electrode, a peak gas flow velocity of VW = 2.54, 2.74, and 1.93 m/s has been obtained for positive, negative, and ac corona discharges. This is 1.95, 1.31, and 1.30 times higher than the velocity VW = 1.30, 2.09, and 1.49 m/s measured with the same design EHD gas pump and a non-porous metal point electrode. At 0.1 W of input corona power for dc and ac powers, the flow generation yields of Y = 13.88, 12.80, and 11.70 m/s/W were obtained with the wet porous point electrode for the positive, negative, and ac corona discharges, which are 1.23, 1.24, and 1.15 times higher as compared with those of the metal point electrode with Y = 11.32, 10.29, and 10.20 m/s/W, respectively. These enhancements may be due to the elevated input corona powers and the water particles generated from the wet porous point electrode.
Methods of determining the desired frequency characteristics of the automatic control systems
Considered the methods of determining the desired frequency characteristics of the automatic control systems while the synthesis of their corrective devices.