This paper describes an experimental and theoretical study on an extraction phenomenon of liquids occurring at an air gap between the liquid surface and the electrode by applying a direct current (DC) or low-frequency...This paper describes an experimental and theoretical study on an extraction phenomenon of liquids occurring at an air gap between the liquid surface and the electrode by applying a direct current (DC) or low-frequency alternating current (AC) voltage. Three liquids with a different physical property;2,3-dihydrodecafluoropenten, palm fatty acid ester oil and crude rapeseed oil are used as working liquids. The electrode configuration is the sphere or plane (high voltage electrode) to grounded plane electrode. The grounded plane electrode is fixed to the bottom of the test vessel with working liquid and the high voltage electrode is installed in an air above the liquid surface against the grounded plane electrode. The liquid surface swells towards the high voltage electrode by the increase of voltage and the liquid is extracted in a short time, thereafter the air gap between the liquid surface and the high voltage electrode is bridged at a thick liquid column. Such the liquid behavior displays unique features with voltage polarity effect for each working liquid. The relationship between the applied voltage, current variation, height of swollen liquid, force pulling liquid and dynamic feature of liquid is examined experimentally. The liquid behavior is considered theoretically based on experimental observations.展开更多
This paper presents an experimental study on the creeping discharge propagating over the pressboard surface in two vegetable oils(PFAE(palm fatty acid ester)oil and CRS(crude rapeseed)oil)and commercial mineral oil un...This paper presents an experimental study on the creeping discharge propagating over the pressboard surface in two vegetable oils(PFAE(palm fatty acid ester)oil and CRS(crude rapeseed)oil)and commercial mineral oil under the quasi-square impulse voltage with any pulse width.The pressboard impregnated with the sample oil is immersed completely into the same oil.The tungsten needle electrode is installed in the pressboard surface with and without the counter electrode to generate a creeping discharge.The other side of pressboard has the thin copper rod as a back side electrode.A comparison of the shape and stopping length of positive and negative streamers,discharge current,emitted light signal,and temporal variation and velocity of streamer propagation is reported for all different oil-pressboard interfaces.It has been shown that the behavior of creeping streamers has unique characteristics and polarity effects,and the traveling mode and propagation velocity of streamers are greatly different depending on the type of oil.展开更多
文摘This paper describes an experimental and theoretical study on an extraction phenomenon of liquids occurring at an air gap between the liquid surface and the electrode by applying a direct current (DC) or low-frequency alternating current (AC) voltage. Three liquids with a different physical property;2,3-dihydrodecafluoropenten, palm fatty acid ester oil and crude rapeseed oil are used as working liquids. The electrode configuration is the sphere or plane (high voltage electrode) to grounded plane electrode. The grounded plane electrode is fixed to the bottom of the test vessel with working liquid and the high voltage electrode is installed in an air above the liquid surface against the grounded plane electrode. The liquid surface swells towards the high voltage electrode by the increase of voltage and the liquid is extracted in a short time, thereafter the air gap between the liquid surface and the high voltage electrode is bridged at a thick liquid column. Such the liquid behavior displays unique features with voltage polarity effect for each working liquid. The relationship between the applied voltage, current variation, height of swollen liquid, force pulling liquid and dynamic feature of liquid is examined experimentally. The liquid behavior is considered theoretically based on experimental observations.
文摘This paper presents an experimental study on the creeping discharge propagating over the pressboard surface in two vegetable oils(PFAE(palm fatty acid ester)oil and CRS(crude rapeseed)oil)and commercial mineral oil under the quasi-square impulse voltage with any pulse width.The pressboard impregnated with the sample oil is immersed completely into the same oil.The tungsten needle electrode is installed in the pressboard surface with and without the counter electrode to generate a creeping discharge.The other side of pressboard has the thin copper rod as a back side electrode.A comparison of the shape and stopping length of positive and negative streamers,discharge current,emitted light signal,and temporal variation and velocity of streamer propagation is reported for all different oil-pressboard interfaces.It has been shown that the behavior of creeping streamers has unique characteristics and polarity effects,and the traveling mode and propagation velocity of streamers are greatly different depending on the type of oil.
