scholarly journals Effects of dynamic deformation of pendant water drops on the electric field between hollow porcelain insulator sheds under extreme rainfall

High Voltage ◽  
2021 ◽  
Author(s):  
Yijie Sun ◽  
Lin Yang ◽  
Gaofeng Shang ◽  
Zhiqiang Kuang ◽  
Yifan Liao ◽  
...  
Keyword(s):  
Electric Field ◽  
Dynamic Deformation ◽  
Extreme Rainfall ◽  
Porcelain Insulator ◽  
Water Drops

The vibration of electrified water drops

1971 ◽  
Vol 322 (1551) ◽  
pp. 523-534 ◽  
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Axial Ratio ◽  
Uniform Electric Field ◽  
Interferometric Technique ◽  
Photographic Analysis ◽  
Wide Range ◽  
Water Drops ◽  
Strength And Deformation ◽  
A Charge

Pressure has been used as the principal parameter in calculations of the fundamental vibrational frequencies of spherical drops of radius R , density ρ, and surface tension T carrying a charge Q or uncharged spheroidal drops of axial ratio a / b situated in a uniform electric field of strength E . Freely vibrating charged drops have a frequency f = f 0 ( 1 - Q 2 /16π R 3 T ) ½ , as shown previously by Rayleigh (1882) using energy considerations; f 0 is the vibrational frequency of non-electrified drops (Rayleigh 1879). The fundamental frequency of an uncharged drop in an electric field will decrease with increasing field strength and deformation a / b and will equal zero when E ( R )/ T ) ½ = 1.625 and a / b = 1.86; these critical values correspond to the disintegration conditions derived by Taylor (1964). An interferometric technique involving a laser confirmed the accuracy of the calculations concerned with charged drops. The vibration of water drops of radius around 2 mm was studied over a wide range of temperatures as they fell through electric fields either by suspending them in a vertical wind tunnel or allowing them to fall between a pair of vertical electrodes. Photographic analysis of the vibrations revealed good agreement between theory and experiment over the entire range of conditions studied even though the larger drops were not accurately spheroidal and the amplitude of the vibrations was large.

Experimental investigation on flashover characteristics of hollow porcelain insulator under extreme rainfall

2022 ◽  
Vol 203 ◽  
pp. 107659
Author(s):  
Lin Yang ◽  
Gaofeng Shang ◽  
Zhiqiang Kuang ◽  
Yijie Sun ◽  
Yifan Liao ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Extreme Rainfall ◽  
Porcelain Insulator

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.

scholarly journals An experimental investigation of the influence of electric field on the collision-coalescence of water drops

Tellus ◽  
1979 ◽  
Vol 31 (4) ◽  
pp. 279-289 ◽  
Author(s):  
S. K. Paul ◽  
A. Mary Selvam ◽  
Bh. V. Ramana Murty
Keyword(s):  
Experimental Investigation ◽  
Electric Field ◽  
Water Drops

Augmentation of Direct-Contact Heat Transfer to Drops with an Intermittent Electric Field

1980 ◽  
Vol 102 (1) ◽  
pp. 32-37 ◽  
Author(s):  
N. Kaji ◽  
Y. H. Mori ◽  
Y. Tochitani ◽  
K. Komotori
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Electric Field ◽  
Transfer Coefficient ◽  
Direct Contact ◽  
Silicone Oil ◽  
Duty Ratio ◽  
Contact Heat ◽  
Contact Heat Transfer ◽  
Water Drops

The characteristics of the augmentation technique previously proposed by the authors has been studied experimentally with water drops 3.9 to 5.9 mm in diameter rising in methylphenyl silicone oil. Each drop is subjected to an intermittent electric field applied periodically perpendicular to its trajectory, and the drop responds by periodic elongation in the direction of the field. The dependence of heat transfer coefficient on the strength, frequency and duty ratio of the field is presented and discussed.

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