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Corona ring

About: Corona ring is a(n) research topic. Over the lifetime, 1503 publication(s) have been published within this topic receiving 14530 citation(s).
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Journal ArticleDOI
Kazimierz Adamiak1, P. Atten2Institutions (2)
Abstract: A numerical technique is proposed for determining the distributions of electric field and charge density in the case of a positive corona discharge in gas in the point–plane geometry. This technique is based on the boundary and finite elements methods for obtaining the harmonic and space charge components of the electric field, respectively, and on the method of characteristics to determine the charge density distribution. The numerical simulation gives the current density distribution on the ground plate, which compares favorably with the ones measured using a cylinder–cone needle with a tip of spherical shape.

205 citations

Journal ArticleDOI
Akira Yabe1, Yasuo Mori1, Kunio Hijikata1Institutions (1)
01 Apr 1978-AIAA Journal
Abstract: The corona wind, with a velocity of several meters per second, is caused by applying high electric tension to bring about corona discharge in gases. In this paper the corona wind is experimentally and theoretically analyzed from an electrohydrod ynamical (EHD) standpoint. Experiments have been performed mainly in nitrogen by a two-dimensional electrode arrangement of a fine wire anode and a plate cathode. The voltage-current characteristics of an electrostatic probe indicate that positive ions predominate in the whole space except in an extremely narrow region close to the wire. A theoretical analysis has been conducted based on the model that positive ions produced by ionization near the wire electrode move toward the plate, introducing the bulk convective motion of neutral molecules as the result of collisions of ions and neutral molecules. The electric potential distribution in the space and pressure distribution on the plate calculated numerically agree well with the experimental data. Consequently, it is made clear that the corona wind is caused by the Coulomb force exerted on ions and collisions of ions and neutral molecules of gas.

191 citations

Journal ArticleDOI
L. Niemeyer1, L. Ullrich1, N. Wiegart1Institutions (1)
Abstract: A survey is given of the present state of understanding of leader breakdown of electronegative gases in nonuniform field gaps and under fast-rising voltage waveforms. The basic physical processes involved are the formation of a pulsed streamer corona, the transformation of one of the streamers into a leader step, the temporal development of the leader channel, and the stepped propagation of the leader through the gap. The growth and structural characteristics of the corona are modeled and the results obtained are used to derive simple approximations for the spatial corona extension and the corona charge. Two leader inception mechanisms are discussed, namely, the stem and the precursor mechanisms. Inception criteria and characteristic time scales are derived for both of them in terms of the experimental parameters. A simplified model, which also predicts the random aspects of leader propagation through the gap, is presented. Some typical gas-insulation design problems are treated as examples. >

158 citations

Richard H. Conrad1Institutions (1)
14 Jun 1990-
Abstract: A method of supplying electrical power to and controlling corona discharge cells used for the generation of ozone employs a single-cycle discontinuous waveform which is characterized by a fixed pulse width and a variable repetition rate. Discrete bipolar pulses are composed of a pair of unipolar pulses of opposite polarity. The bipolar pulse repetition rate is varied to control the average corona power, providing an infinite turndown of ozone output. When powering discharge cells which are asymmetric in their response to pulse polarity, such as those containing a dielectric coated with a conducting surface as a first electrode and a metal as a second electrode, the present invention configures the first pulse of each pair to make the dielectric electrode electronically negative with respect to the metal electrode. This polarity sequence produces a more stable corona and far less electrical noise. Furthermore, to decrease acoustic and mechanical resonances and fatigue to system components and to the human ear, this invention broadens the frequency distribution of the pulse repetition rate by repetitively sweeping or randomly jittering the intervals between bipolar pulses.

152 citations

13 Oct 2000-
Abstract: An electrostatic fluid accelerator having a multiplicity of closely spaced corona electrodes (1). The close spacing of such corona electrodes (1) is obtainable because such corona electrodes (1) are isolated from one another with exciting electrodes (2). Either the exciting electrode (2) must be placed asymmetrically between adjacent corona electrodes (1) or an accelerating electrode must be employed. The accelerating electrode can be either an attracting (13) or a repelling electrode (19). Preferably, the voltage between the corona electrodes (1) and the exciting electrodes (2) is maintained between the corona onset voltage and the breakdown voltage with a flexible top high-voltage power supply. Optionally, however, the voltage between the corona electrodes (1) and the exciting electrodes (2) can be varied, even outside the range between the corona onset voltage and the breakdown voltage, in order to vary the flow of fluid. And, to achieve the greatest flow of fluid, multiple stages (28, 29 and 30) of the individual Electrostatic Fluid Accelerator are utilized with a collecting electrode (31 or 32) between successive stages (28, 29 and 30) in order to preclude substantially all ions and other electrically charged particles from passing to the next stage (28, 29 or 30), where they would tend to be repelled and thereby impair the movement of the fluid. Finally, constructing the exciting electrode (2) in the form of a plate that extends downstream with respect to the desired direction of fluid flow also assures that more ions and, consequently, more fluid particles flow downstream.

133 citations

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