Space-Resolved Modeling of Stationary Spots on Copper Vacuum Arc Cathodes and on Composite CuCr Cathodes With Large Grains

Benilov, M. S.; Cunha, M D; Hartmann, Werner; Kosse, S.; Lawall, A.; Wenzel, N.

doi:10.1109/tps.2013.2263255

Cited by 27 publications

(41 citation statements)

References 41 publications

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“…For comparison, also shown are distributions of temperature on cathodes made of pure copper (R Cr = 0) and pure chromium (R Cr = ∞). Similar to what happens for cathodes made of pure copper and pure chromium [13], there is a well-pronounced spot with a virtually constant temperature of the cathode surface. Distributions of other parameters are skipped for brevity and we note only that similar to what happens for cathodes made of pure metals, the spot edge may be identified with the maximum in the distribution of the density of energy flux from the plasma; the current outside the spot is negligible; the maximum of distribution of potential in the cathode body occurs on the surface at the center of the spot.…”

Section: Stationary Spots Attached To Cr Grains In Cu Matrixsupporting

confidence: 62%

“…The model allows one to simulate the cathode and the near-cathode plasma layer independently of the arc column and sometimes is called the model of nonlinear surface heating. The model is used in the theory and modeling of arcs in ambient gas (see [15]- [22] as examples of more recent references) and has been extended to vacuum arcs [13]. In this paper, the model of nonlinear surface heating has been used in the same form as in [13] and its description is skipped for brevity; we only note that the specific heats of copper and chromium have been evaluated with the use 0093-3813 © 2015 IEEE.…”

Section: Modelmentioning

confidence: 99%

“…2-D numerical modeling of vacuum arc spots is reported in [5]- [14]. In particular, in [12] and [13] cathode spots on composite CuCr contacts have been studied in the case where chromium grains are large, which occurs at initial stages of life of contacts of highpower circuit breakers. It was found that in this case spots with currents of the order of tens of amperes operating on the copper matrix coexist with spots with currents of the order of one or few amperes on chromium grains.…”

mentioning

confidence: 99%

“…It was found that in this case spots with currents of the order of tens of amperes operating on the copper matrix coexist with spots with currents of the order of one or few amperes on chromium grains. This paper represents a continuation of [12] and [13] and is concerned with simulation of spots attached to Cr grains in the Cu matrix in a wide range of values of the ratio of the grain radius to the radius of the spot. Also studied is the stability of stationary spots as well as the sensitivity of the obtained results with respect to variations in different aspects of the simulation model.…”

mentioning

confidence: 99%

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Modeling Spots on Composite Copper–Chromium Contacts of Vacuum Arcs and their Stability

Benilov

Cunha

Hartmann

et al. 2015

IEEE Trans. Plasma Sci.

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Cathode spots on copper-chromium contacts of vacuum interrupters are simulated by means of a self-consistent space-resolved numerical model of cathode spots in vacuum arcs developed on the basis of the COMSOL Multiphysics software. Attention is focused on spots attached to Cr grains in the Cu matrix in a wide range of values of the ratio of the grain radius to the radius of the spot. In the case where this ratio is close to unity, parameters of spot are strongly different from those operating on both pure-copper and pure-chromium cathodes; in particular, the spot is maintained by Joule heat generation in the cathode body and the net energy flux is directed from the cathode to the plasma and not the other way round. An investigation of stability has shown that stationary spots are stable if current controlled. However, under conditions of highpower circuit breakers, where the near-cathode voltage is not affected by ignition or extinction of separate spots, the spots are unstable and end up either in explosive-like behavior or in destruction by thermal conduction. On the other hand, spots live significantly longer-up to one order of magnitude-if the spot and grain sizes are close; else, typical spot lifetimes are of the order of 10 µs. This result is very interesting theoretically and may explain the changes in grain size occurring in the beginning of the lifetime of contacts of high-power current breakers. A sensitivity study has shown that variations in different aspects of the simulation model produce quantitative changes but do not affect the results qualitatively.

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Section: Stationary Spots Attached To Cr Grains In Cu Matrixsupporting

confidence: 62%

Section: Modelmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Modeling Spots on Composite Copper–Chromium Contacts of Vacuum Arcs and their Stability

Benilov

Cunha

Hartmann

et al. 2015

IEEE Trans. Plasma Sci.

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“…In fact, there are published self-consistent 2D simulations of stationary cathode spots 14,15 which is useful to be considered as the boundary conditions of cathode spots jet, but in this paper, in order to simplify the calculation, we just use current boundary conditions, and more complete boundary conditions will be considered in the future.…”

Section: E Influence Of Different Height Of Mixing Zonementioning

confidence: 99%

Modeling of mixing and interaction of multi-cathode spot vacuum arc jets

et al. 2016

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Vacuum arc consists of cathode spot and mixing zone, arc column and anode zone. The separate jets and the mixing zone should be considered in the model of diffuse arc. Moreover, the interaction between the plasma jets in multi-cathode spot vacuum arc also is very important. In this paper, mixing and interaction of multi-cathode spot vacuum arc jets were studied through simulation. To completely investigate the mixing and interaction of vacuum arc jets, a steady 3D Magneto-Hydro-Dynamic (MHD) modeling was established. In order to find out the influence of different parameters on mixing and interaction of vacuum arc jets, simulations with different parameters such as currents, angel of vacuum arc jets, with or without electromagnetic equations, tilted jets and different height of mixing zone were conducted. The simulation results show that the densities of ion number and plasma pressure as well as ion temperature increase with the increase of arc current, while the plasma velocity decreases. The jet center is more deviated from the cathode center with the increase of angle of tilted jets.

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Element- and charge-state-resolved ion energies in the cathodic arc plasma from composite AlCr cathodes in argon, nitrogen and oxygen atmospheres

Franz

Polcik

Anders

2015

Surface and Coatings Technology

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The energy distribution functions of ions in the cathodic arc plasma using composite AlCr cathodes were measured as a function of the background gas pressure in the range 0.5 to 3.5 Pa for different cathode compositions and gas atmospheres. The most abundant aluminium ions were Al+ regardless of the background gas species, whereas Cr2+ ions were dominating in Ar and N2 and Cr+ in O2 atmospheres. The energy distributions of the aluminium and chromium ions typically consisted of a high-energy fraction due to acceleration in the expanding plasma plume from the cathode spot and thermalised ions that were subjected to collisions in the plasma cloud. The fraction of the latter increased with increasing background gas pressure. Atomic nitrogen and oxygen ions showed similar energy distributions as the aluminium and chromium ions, whereas the argon and molecular nitrogen and oxygen ions were formed at greater distance from the cathode spot and thus less subject to accelerating gradients. In addition to the positively charged metal and gas ions, negatively charged oxygen and oxygen-containing ions were observed in O2 atmosphere. The obtained results are intended to provide a comprehensive overview of the ion energies and charge states in the arc plasma of AlCr composite cathodes in different gas atmospheres as such plasmas are frequently used to deposit thin films and coatings.

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Space-Resolved Modeling of Stationary Spots on Copper Vacuum Arc Cathodes and on Composite CuCr Cathodes With Large Grains

Cited by 27 publications

References 41 publications

Modeling Spots on Composite Copper–Chromium Contacts of Vacuum Arcs and their Stability

Modeling Spots on Composite Copper–Chromium Contacts of Vacuum Arcs and their Stability

Modeling of mixing and interaction of multi-cathode spot vacuum arc jets

Element- and charge-state-resolved ion energies in the cathodic arc plasma from composite AlCr cathodes in argon, nitrogen and oxygen atmospheres

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