Production of water drops and corona due to rupture of air bubbles at water surface under a positive dc electric field

2001 ◽  
Vol 53 (3) ◽  
pp. 209-219 ◽  
Author(s):  
Toshiyuki Sugimoto ◽  
Yoshio Higashiyama
Keyword(s):  
Electric Field ◽  
Water Surface ◽  
Air Bubbles ◽  
Dc Electric Field ◽  
Water Drops

The Lobe Structure in Ice Accreted on an Aluminium Conductor in The Presence of a Dc Electric Field

1983 ◽  
Vol 4 ◽  
pp. 228-235 ◽  
Author(s):  
Luan C. Phan ◽  
Jean-Louis Laforte ◽  
Du D. Nguyen
Keyword(s):  
Electric Field ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Air Bubbles ◽  
Experimental Conditions ◽  
Charged Droplets ◽  
Water Drops ◽  
The Difference ◽  
Negative Electric Field ◽  
Corona Wind

Supercooled droplets of 38 μm mean volume diameter are accreted on a smooth aluni mum cylinder of 3.15 cm in diameter in order to study the effect of an electrostatic field upon ice formation on a power-line conductor. The results obtained show that ice grown in the presence of an applied negative field of 15 kV cm−1 exhibits a cusped-lobe structure characterized by surfacial outward knobs, convex rings of fine air bubbles and radial lines of large air bubbles; in the same conditions, a positive electric field of 15 kV cm−1 does not produce such lobe features. On the other hand, accretion tests performed in the absence of an electric field with a 33 μm droplet spectrum show that the well-developed cusped-lobe structure appears in ice at low ambient temperature and air velocity. In the present experimental conditions, the formation of cusped lobes observed in the presence of a negative electric field could be explained by a decrease in the temperature of the deposit due to a reduction of impact velocity of the charged droplets and/or an increase in the local heat-transfer coefficient at the surface of the ice accretion. Corona wind from ice points, always in the opposite direction to the impinging droplets, may also reduce their impact velocities. In addition, corona wind and roughness of the surface may contribute to a better evacuation of the latent heat and thus decrease the deposit temperature. The difference between the effects of a negative DC field and those of a DC positive field of the same strength comes from a stronger ionization intensity and/or a stronger deformation of water drops in the negative electric field.

Study on Discharge of Separated Water Droplets in DC Field

2011 ◽  
Vol 130-134 ◽  
pp. 3276-3279
Author(s):  
Zong Xi Zhang ◽  
Shan Feng Yin
Keyword(s):  
Electric Field ◽  
Hydrophobic Surface ◽  
Electrical Equipment ◽  
Water Droplets ◽  
Surface Flashover ◽  
Voltage Drops ◽  
Flashover Voltage ◽  
Dc Electric Field ◽  
Water Drops ◽  
And Migration

With the accelerating construction of strong smart grid, and the grid voltage level rising, performance requirements for the electrical insulation of electrical equipment also continue to increase. In terms of the advantages of RTV on antifouling, RTV-based paints coated insulator coating capacity of its flash tolerance can significantly increase, mainly due to RTV coating hydrophobic hydrophobicity and migration. But when the hydrophobic surface is in the fully wet, many small drops of water in the surface will be gathered into big drops of water, and these large droplets will distort the surface electric field of the medium. So the flashover voltage of the hydrophobic surface’s separated water droplets under DC electric field are analyzed comparatively in this paper, while some influencing factors such as different medias and volume of water drops, are introduced in specific experiments, and their effects on the flashover voltage are analyzed; under DC electric field experiment on the surface of hydrophobic and hydrophilic surface flashover voltage drops separation characteristics were studied.

Corona produced by splashing of water drops on a water surface in a strong electric field

1973 ◽  
Vol 44 (7) ◽  
pp. 3082-3086 ◽  
Author(s):  
Christopher T. Phelps ◽  
Richard F. Griffiths ◽  
Bernard Vonnegut
Keyword(s):  
Electric Field ◽  
Water Surface ◽  
Strong Electric Field ◽  
Water Drops

The Flashover Phenomena due to Water Drops on Insulating Surface under DC Electric Field

2014 ◽  
Vol 931-932 ◽  
pp. 962-967 ◽  
Author(s):  
Sackthavy Chandavong ◽  
Kittipong Tonmitra ◽  
Arkom Kaewrawang
Keyword(s):  
Electric Field ◽  
Epoxy Resin ◽  
Direct Current ◽  
Water Drop ◽  
Tap Water ◽  
Water Volume ◽  
Electric Field Line ◽  
Insulating Surfaces ◽  
Dc Electric Field ◽  
Water Drops

This paper presents the flashover between the electrodes conducted the current by the water drop on insulating surfaces. It causes ageing to the insulator and leads to deterioration when the insulator is used for over years. In the experiments, epoxy resin with the water drop is tested by using direct current until flashover of 70 kV. Besides that, the effect of the water volume, the number of the water drop and the water types - tap and aqua water on flashover are investigated. The flashover of tap water grows faster when increases the volume of water drop. The flashover of aqua water does not depend on the volume of water drop. The deformation and elongate of water drop is in the direction of electric field line. The results lead to protect the damage of insulator caused by the humidity and the loss of their efficiency insulators.

The Lobe Structure in Ice Accreted on an Aluminium Conductor in The Presence of a Dc Electric Field

1983 ◽  
Vol 4 ◽  
pp. 228-235
Author(s):  
Luan C. Phan ◽  
Jean-Louis Laforte ◽  
Du D. Nguyen
Keyword(s):  
Electric Field ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Air Bubbles ◽  
Experimental Conditions ◽  
Charged Droplets ◽  
Water Drops ◽  
The Difference ◽  
Negative Electric Field ◽  
Corona Wind

Supercooled droplets of 38 μm mean volume diameter are accreted on a smooth aluni mum cylinder of 3.15 cm in diameter in order to study the effect of an electrostatic field upon ice formation on a power-line conductor. The results obtained show that ice grown in the presence of an applied negative field of 15 kV cm−1exhibits a cusped-lobe structure characterized by surfacial outward knobs, convex rings of fine air bubbles and radial lines of large air bubbles; in the same conditions, a positive electric field of 15 kV cm−1does not produce such lobe features. On the other hand, accretion tests performed in the absence of an electric field with a 33 μm droplet spectrum show that the well-developed cusped-lobe structure appears in ice at low ambient temperature and air velocity. In the present experimental conditions, the formation of cusped lobes observed in the presence of a negative electric field could be explained by a decrease in the temperature of the deposit due to a reduction of impact velocity of the charged droplets and/or an increase in the local heat-transfer coefficient at the surface of the ice accretion. Corona wind from ice points, always in the opposite direction to the impinging droplets, may also reduce their impact velocities. In addition, corona wind and roughness of the surface may contribute to a better evacuation of the latent heat and thus decrease the deposit temperature. The difference between the effects of a negative DC field and those of a DC positive field of the same strength comes from a stronger ionization intensity and/or a stronger deformation of water drops in the negative electric field.

scholarly journals Erratum: Corona produced by splashing of water drops on a water surface in a strong electric field

1974 ◽  
Vol 45 (2) ◽  
pp. 977-977
Author(s):  
Christopher T. Phelps ◽  
Richard F. Griffiths ◽  
Bernard Vonnegut
Keyword(s):  
Electric Field ◽  
Water Surface ◽  
Strong Electric Field ◽  
Water Drops
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