| Budget Amount *help |
¥3,810,000 (Direct Cost: ¥3,600,000、Indirect Cost: ¥210,000)
Fiscal Year 2007: ¥910,000 (Direct Cost: ¥700,000、Indirect Cost: ¥210,000)
Fiscal Year 2006: ¥2,900,000 (Direct Cost: ¥2,900,000)
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| Research Abstract |
The filtration speed of charge injection type of electrostatic oil filter is increased with the increase in the number density of projections, the applied voltage, and in the oil temperature and with the decrease in the electrode spacing but the speed tends to be saturated at higher applied voltages and oil temperatures. In this investigation, in order to make clear those characteristics, the flow field is measured using a two-dimensional filter model. The flow and electric fields are simulated by numerical analysis and are compared between simulation and experiment. In addition, the effects of the shape and position of collectors, which are inserted between the electrodes to capture conductive contaminants like metallic wear debris, on the filtration speed are investigated. The following results are obtained:
(1) Ion drag flow is generated from the projection tips of the emitter electrode towards the smooth electrode due to the action of Coulomb force exerted on the injected charges. T
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he magnitude of the flow is increased with increasing applied voltage, is decreased with decreasing electrode spacing, and is larger for negative charge injection than for positive charge injection.
(2) More charges are apt to be injected and then faster ion drag flow is generated at higher oil temperatures.
(3) When the layer of particles captured on the smooth electrode is relatively thick and the ion drag flow is relatively fast, part of the particles captured on the smooth electrode is detached by the action of the ion drag flow.
(4) Taking the above results into account, the ion drag flow is-considered to be the principal cause of the saturation of the filtration speed at higher applied voltages and temperatures.
(5)Numerical simulation results qualitatively agree with measured ones. It is expected that the flow and electric fields in a real three-dimensional electrostatic filter can be predicted by improving the simulation accuracy.
(6)The filtration speed depends on the shape and position of the collectors inserted between the electrodes. It is useful to insert the collectors at the positions of the projection tips of the emitter electrode. Less
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