Electrical and thermal conductivities and enthalpy of high‐temperture air contaminated by copper vapor

Sakuta, Tadahiro; Kito, Yukio; Miyachi, Iwao

doi:10.1002/eej.4391010208

Cited by 11 publications

(11 citation statements)

References 11 publications

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“…According to Ref. [2], the electrical conductivity of air is affected by the contamination rate of Cu vapor and gas temperature. If the gas temperature is less than 10 000 K, the electrical conductivity of the gas is proportional to the metal vapor concentration rate when the contamination rate is less than 10%.…”

Section: Simulation Results and Analysesmentioning

confidence: 99%

“…The contamination of metal vapor in the arc plasma can significantly increase the gas electrical conductivity [2–4] because the metal vapor (Cu atom) is generated from the electrodes, and its lower ionization voltage causes an increase in electron‐number density [5]. Therefore, it is hypothesized that the arc stretches into the extinguishing chamber under the effect of an external magnetic field; however, the metal vapor (atom and ion) remains on the electrode surface and the area between them owing to the residual temperature of the electrode surface, even after the arc column moves forward.…”

Section: Introductionmentioning

confidence: 99%

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Analysis of Adverse Influence of Metal Vapor to Arc Movement Between Electrodes with External Magnetic Field Applied by Numerical Simulation

Ren

Nemoto

Suzuki

et al. 2021

IEEJ Transactions Elec Engng

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The demand and sustainable development goals for electric vehicles (EVs) have been increasing. A quick charging circuit is an essential technology for EVs. To protect this circuit from faults or accidents, rapid interruption of the arc generated by the switching of direct current contactors (DCCs) is required. However, the DCCs have small sizes and close boundaries against an arc stretch toward the extinguishing chamber. The metal vapor generated by the electrodes causes the arc to remain between the electrodes instead of stretching forward, because the gas electrical conductivity increases when the metal vapor contaminates it. In this study, the arc movements with and without consideration of the metal vapor were simulated numerically to elucidate the influence of metal vapor on arc mobility. It was observed that the metal vapor generated from the electrodes causes the reattachment phenomenon to occur several times on the anode side, which increases the time of arc stretching into the extinguishing chamber. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

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Section: Simulation Results and Analysesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Analysis of Adverse Influence of Metal Vapor to Arc Movement Between Electrodes with External Magnetic Field Applied by Numerical Simulation

Ren

Nemoto

Suzuki

et al. 2021

IEEJ Transactions Elec Engng

View full text Add to dashboard Cite

show abstract

“…9, the calculated energy density decreased somewhat as the iron vapor concentration increased. The reason of the result is that the high temperature air mixed with iron vapor doesn't tend to be effected by the decomposition in comparison with high temperature air, and therefore the enthalpy of high temperature air mixed with iron vapor was lower than that of high temperature air (16) . As described above, the iron vapor concentration in the arc jet was low (1-10%) when the arc current was 10-20 kA, and the iron vapor concentration was high (50%) when the arc current was 30-50 kA.…”

Section: Discussionmentioning

confidence: 97%

Temperature, Iron Vapor Concentration and Energy Density for Arc Jets of 10-50 kA AC Arcs in a Long Gap

et al. 2005

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MemberArc jets that spout from electrodes as a result of high current fault arcs cause damage to the surrounding apparatus. This paper describes the results of spectroscopic observation of 10-50 kA AC arc jet. The electrodes used were iron of 40 mm in diameter. The temperature and the iron vapor concentration of the arc jet were determined by considering the self-absorption of two spectral lines of iron atom. As the arc current increased from 10 kA to 50 kA, the temperature gradually decreased from 14,000 K to 10,000 K, and the iron vapor concentration (molar rate) in the arc jet increased abruptly from 1% to 50%. The energy density was calculated and it was found that the energy density of the arc jet did not change greatly (8 × 10 5 J/m 3 ) as the arc current increased from 10 kA to 50 kA.

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“…According to Sakuta et al . , the electrical conductivity of air is affected by the contamination rate of Cu vapor and temperature. If the temperature is less than 10 000 K, the electrical conductivity of air increases with increase in the concentration of Cu vapor when the contamination rate is less than 1%.…”

Section: Hypothesis Establishmentmentioning

confidence: 99%

Three‐dimensional electromagnetic thermal fluid simulation of re‐strike phenomenon in magnetically driven arc between parallel electrodes with edges

Ren

Kokubo

Maeda

et al. 2020

IEEJ Transactions Elec Engng

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A magnetically driven arc does not advance smoothly between parallel electrodes with edges. The anode spot stagnates on the anode surface when the arc column and cathode spot move forward. According to experimental results, when the arc column moves closer to the anode surface, or a high‐temperature gas comes into contact with the anode, a new anode spot appears and electrical breakdown occurs. Meanwhile, the original anode spot disappears. It is well known as the re‐strike phenomenon. Also, it can be observed using a bandpass filter (520 nm) that a large amount of Cu vapor is generated whenever a new anode spot appears. Because the Cu vapor considerably increases the arc's radiative emission and has a dissimilar effect on the gas's electrical conductivity at different concentrations, a three‐dimensional electromagnetic thermal fluid simulation program that considers the metal vapor from the electrodes is proposed in this paper. Based on the experimental figures, it is able to simulate the re‐strike process by controlling the electrical conductivity of the control volume at the anode surface. In addition, the physical properties of the arc plasma, the original anode spot area, and the re‐strike point area are analyzed, in order to elucidate the occurrence conditions of the re‐strike phenomenon. The results show that the arc form is affected by the electrode jets, which leads to an increase in the electric field density between the re‐strike point and the arc column, thereby causing the re‐strike phenomenon to occur. © 2020 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

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Electrical and thermal conductivities and enthalpy of high‐temperture air contaminated by copper vapor

Cited by 11 publications

References 11 publications

Analysis of Adverse Influence of Metal Vapor to Arc Movement Between Electrodes with External Magnetic Field Applied by Numerical Simulation

Analysis of Adverse Influence of Metal Vapor to Arc Movement Between Electrodes with External Magnetic Field Applied by Numerical Simulation

Temperature, Iron Vapor Concentration and Energy Density for Arc Jets of 10-50 kA AC Arcs in a Long Gap

Three‐dimensional electromagnetic thermal fluid simulation of re‐strike phenomenon in magnetically driven arc between parallel electrodes with edges

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