Erosion of a Copper Cathode in a Nonstationary Arc Spot. I. Experimental Investigation

Esipchuk, A. M.; Marotta, A.; Sharakhovskii, L. I.

doi:10.1023/b:joep.0000028518.06494.f4

Cited by 4 publications

(3 citation statements)

References 13 publications

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“…The existence of two regimes -those of micro-and macroerosion -was shown earlier in [7,8]. Here we have assumed that it is a sharp increase in the intensity of the radiated copper line that corresponds to the onset of macroerosion, which is stimulated by the macrofusion in the spot, in accordance with a thermal erosion model [6][7][8][9][10].…”

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confidence: 85%

“…As has been mentioned above, An'shakov et al [2,3] assumed that the disturbance of vortex stabilization of the arc by cathode jets could mainly cause the sharp increase in erosion observed (the microerosion becoming macroerosion). However, we showed in [7][8][9] that an analogous passage from micro-to macroerosion was also observed in axial vortex-free feeding of the gas and purely magnetic movement of the arc. Therefore, we assumed that the initial physical cause of the increase in erosion was the cathode reaching the critical thermal regime, in which macrofusion causing the ejection of cathode jets observed in [2] began in the spot, rather than the destruction of the vortex.…”

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confidence: 99%

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Investigation of the parameters of a nonstationary arc spot on a copper cathode by the thermospectroscopic method. II. Dynamics of movement of the spot

Bublievskii

Marotta

Esipchuk

et al. 2005

J Eng Phys Thermophys

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Indirect data on the features of the dynamics of a cathode spot in different erosion regimes have been obtained by investigation of the fluctuations of the intensity of radiation from the arc of the 5218 A° CuI copper spectral line modulated by the rotational frequency in a magnetic field. It has been revealed that the velocity of the cathode spot in the regime of intense radiation of this line in macroerosion is always lower than that in the regime of weak radiation in microerosion, whereas the variance of its distribution is, conversely, higher. A hypothesis for the relationship between the line-radiation intensity and the occurrence of a cathode copper-vapor jet affecting the mobility and dynamics of the spot and, in terms of them, the erosion has been proposed.Introduction. As has been reported in [1], to determine the density of the current in a cathode arc spot by the thermospectroscopic method we measured the intensity of the radiation of the 5218 A° CuI spectral line of copper from the arc rotating in a coaxial gap in a magnetic field. The beginning of an intense radiation of this line was taken as the beginning of macrofusion in the spot and the beginning of macroerosion, i.e., an intense form of erosion, instead of the low-intensity one called "microerosion." In [2,3], in experiments on a vortex electric-arc heater (EAH), An'shakov et al. observed the outflow of high-power cathode jets from the spot in passage of erosion from the lowintensity form to an intense one; these jets destroyed the structure of the vortex flow and disturbed regular rotation of the arc. This disturbance of the vortex stabilization of discharge was considered by An'shakov et al. to be predominantly responsible for the erosion becoming intense. Since we recorded the rotational velocity of the arc in both regimes -before the increase in the intensity of the copper spectral line and after it, which, presumably, corresponded to the regimes of micro-and macroerosion, the results of such recording also had to contain information on the features of the arc motion in them in the total absence of vortex stabilization of the discharge. To obtain this information we carried out special processing of the experimental results.Experimental Procedure. The experiments were carried out on a coaxial electric-arc unit with magnetic movement of the arc and axial feeding of a gas to the discharge zone. The unit had been described earlier (see [4,5]) in detail; therefore, we do not give its description here. In these experiments, the image of the entire coaxial interelectrode gap with an electric arc moving in its circle was projected onto the section of a light guide, after which the light signal was fed to the entrance slit of a spectrometer. A small segment of the aperture of the interelectrode gap was covered by an opaque screen. Owing to this, the light signal was modulated by the rotational frequency of the arc in the gap.Applying the fast Fourier transformation in the Origin program to processing of the signal of the line intensity recorded wit...

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confidence: 99%

Investigation of the parameters of a nonstationary arc spot on a copper cathode by the thermospectroscopic method. II. Dynamics of movement of the spot

Bublievskii

Marotta

Esipchuk

et al. 2005

J Eng Phys Thermophys

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“…Comprehensive studies aiming to investigate the arc plasma properties, 1 simulate the arc interacting with solid counterparts, [2][3][4] explore the wall ablation and metal evaporation effect on arc dynamics, [5][6][7][8][9][10][11][12][13] and reveal the physics of arc spot [13][14][15][16] have been conducted in the past decades. Rong's group 2,5,11,13,15,17 has extensively studied the arc spot modeling, wall ablation, metal erosion, ferromagnetic effect of steels splitters, and conducted relevant experiments for validation.…”

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Study of wall ablation on low-voltage arc interruption: The effect of Stefan flow

Huo

Selezneva

Jacobs³

et al. 2019

Journal of Applied Physics

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Low-voltage circuit breakers provide essential protection for industrial and residential power installations, by taking advantage of the voltage drop at the electrode–plasma interface to force current zero. This is accomplished by using the magnetic force and unbalanced pressure on the arc as the contacts open to push the arc toward a stack of steel plates that break the arc into subarcs and thereby multiply the number of voltage drops. As the fault current can be high, substantial energy can be dissipated, which results in interactions among the arc and solid counterparts in terms of wall ablation and metal evaporation. In this study, ablation experiments are conducted to demonstrate its great influence on the arc voltage and on the pressure field. Significant progress has been accomplished in the computation of arc dynamics through the coupling of fluid motion with electromagnetics, although an important mechanism in arc breaking simulation, the effect of Stefan flow caused by species generation, has not been considered. We report out a numerical approach for taking into account the effect of Stefan flow, particularly for the breakers with high gasifying wall materials. This approach accounts for the diffusion induced convection due to added-in species from the evaporation surfaces, which will largely influence the flow field and the properties of the plasma mixture. Apart from the voltage drop, this mechanism plays an important role in simulating arc interruption. The ability of conducting Stefan flow computation further enhances the understanding of arc behaviors and improves the design of practically oriented low-voltage circuit breakers.

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Erosion of a Copper Cathode in a Nonstationary Arc Spot. II. Determination of the Energy Parameters of the Arc Spot by the Thermophysical Method

Sharakhovskii

Esipchuk

Marotta

2004

Journal of Engineering Physics and Thermophysics

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Erosion of a Copper Cathode in a Nonstationary Arc Spot. I. Experimental Investigation

Cited by 4 publications

References 13 publications

Investigation of the parameters of a nonstationary arc spot on a copper cathode by the thermospectroscopic method. II. Dynamics of movement of the spot

Investigation of the parameters of a nonstationary arc spot on a copper cathode by the thermospectroscopic method. II. Dynamics of movement of the spot

Study of wall ablation on low-voltage arc interruption: The effect of Stefan flow

Erosion of a Copper Cathode in a Nonstationary Arc Spot. II. Determination of the Energy Parameters of the Arc Spot by the Thermophysical Method

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