Thomson scattering diagnostics of decay processes of Ar/SF<sub>6</sub>gas-blast arcs confined by a nozzle

Tomita, Kentaro; Gojima, Daisuke; Nagai, Kazuhiko; Uchino, Kenji; Kamimae, Ryo; Tanaka, Yasunori; Suzuki, Koji; Iijima, Tadashi; Uchii, Toshiyuki; Shinkai, Takeshi

doi:10.1088/0022-3727/46/38/382001

Cited by 26 publications

(26 citation statements)

References 23 publications

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“…Our results can be compared with a previous measurement of the electron density in an axially blown arc [19,38]. In that work, measurements at several radial points were performed using Thomson scattering for an arc cooled by a constant volume flow of argon of 100 l=min at a pressure of approximately 1 bar.…”

Section: Discussionmentioning

confidence: 88%

“…This peak electron density is roughly 7 times higher than the value reported in Refs. [19,20]. The measurements described in Refs.…”

Section: Discussionmentioning

confidence: 99%

“…The measurements described in Refs. [19,20] were performed in the nozzle throat, which has a diameter of 10 mm, giving a flow speed of roughly 21 m=s. Our measurements are made in the stagnation point.…”

Section: Discussionmentioning

confidence: 99%

“…[11] is particularly interesting for the study of circuit-breaker arcs near current zero because it has the potential to provide information about the heavyparticle density (and, given information about the pressure distribution, the temperature) and the electron density in the phase leading to current zero simultaneously. Thomson scattering, which falls into neither of the two categories above, can also be used to measure the electron density and temperature in an arc [19]. It is difficult, however, to obtain spatially resolved data with this technique [20].…”

Section: Introductionmentioning

confidence: 99%

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Measuring Density Profiles of Electrons and Heavy Particles in a Stable Axially Blown Arc

et al. 2017

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Two-color spatial carrier wave interferometry employing pulsed 532-and 671-nm lasers is used to measure the electron-density and heavy-particle-density profiles in the stagnation point of a stable, axially blown arc in argon for currents of 50 to 200 A and stagnation point pressures of 0.2 to 16 bar. This technique takes advantage of the fact that the free-electron contribution to the refractive index depends strongly on the wavelength, while that of the heavy particles does not. The high spatial resolution achieved allows the hot core of the arc to be readily distinguished from the surrounding boundary layer. A custom-built test device is used to ensure flow conditions that lead to a stable, axisymmetric arc; this permits the reconstruction of the density and temperature profiles using a single projection (interferometric image) of the refractive-index distribution through the arc (at two wavelengths). The arc radius determined from the heavy-particle density decreases with increasing stagnation pressure and increases with the current. These measurements are in good agreement with a simple axially blown arc model taking into account Ohmic heating, radiation losses, and enthalpy flow for core temperatures of approximately 16 500 K. The measured electron density at the center of the arc agrees well with a prediction based on local thermodynamic equilibrium.

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Section: Discussionmentioning

confidence: 88%

“…This peak electron density is roughly 7 times higher than the value reported in Refs. [19,20]. The measurements described in Refs.…”

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Measuring Density Profiles of Electrons and Heavy Particles in a Stable Axially Blown Arc

et al. 2017

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“…For the experiment, we use a DC current source and a power semiconductor, insulated gate bi-polar transistor (IGBT) to control current and voltage for the arc plasmas with an accuracy in time. Previously, the arc behavior and electron density in the arcs in the gas flow were measured in detail by using a laser Thomson scattering (LTS) under free recovery condition of the arcs [1], [2]. In addition to these, the arc behavior has been observed using a high speed video camera for visible light from the arc.…”

mentioning

confidence: 99%

Evaluation on current interruption ability of CO2 and SF6 using current and voltage application highly controlled by power semiconductors

Nakano

Murai

Tanaka

et al. 2015

2015 3rd International Conference on Electric Power Equipment – Switching Technology (ICEPE-ST)

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Abstract-This paper reports a new simple test technique to evaluate current interruption ability of arc quenching gases. In the test, current and voltage applied to the arc was controlled using a insulated gate bipolar transistor (IGBT). Switching the IGBT enables us to produce free recovery conditions for a fundamental arc decay in nozzles. In addition to this, a voltage was intentionally applied to the free recovery arcs between the electrodes by switching-off IGBT again at the specified delay time t d . This applied voltage is called quasi transient recovery voltage (quasi-TRV). We can evaluate successful interruption or interruption failure by measuring the current between the electrodes after quasi-TRV application. We compared the interruption ability of SF6 and CO2 through this developed technique. The experimental results show that a residual arc in SF6 gas flow decays four times more rapidly than that in CO2 gas flow. Influence of observation holes in the nozzles used in the experiments was also investigated, showing less influence of observation on the arc behavior.

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Numerical thermofluid simulation of a decaying arc behavior in CO₂/O₂/C₅F₁₀O (C5‐PFK) considering more than nona‐atomic molecules

Demura

Tanaka

Uesugi

et al. 2019

IEEJ Transactions Elec Engng

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The present article describes numerical thermofluid simulation results on decaying arc behavior in 80%CO 2 + 10%O 2 + 10%C 5 F 10 O (C5-PFK) gas considering molecules constituted with more than 9 atoms in a nozzle space on the assumption of local thermodynamic equilibrium (LTE) condition. The gas mixture 80%CO 2 + 10%O 2 + 10%C 5 F 10 O (C5-PFK) is one of the candidate alternatives for SF 6 in a gas circuit breaker. First, we calculated 80%CO 2 + 10%O 2 + 10%C 5 F 10 O (C5-PFK) arc characteristics only by considering less than 8-atom molecules. However, it seems possible to produce more than nona-atomic molecules in the low-temperature region in 80%CO 2 + 10%O 2 + 10%C 5 F 10 O (C5-PFK) arcs. The present work further calculated the equilibrium composition of this gas mixture at 0.1 MPa with taking account more than nona-atomic molecules. Furthermore, their thermodynamic and transport properties were also computed with collision integrals between species considered. Using these properties, the arc temperature and gas flow fields were calculated using two-dimensional LTE model for a free recovery condition from dc 50 to 0 A. Results showed that a similar temperature decay was obtained for arcs in the 80%CO 2 + 10%O 2 + 10%C 5 F 10 O (C5-PFK) gas mixture to that for arcs in 100%CO 2 gas.

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Thomson scattering diagnostics of decay processes of Ar/SF₆gas-blast arcs confined by a nozzle

Cited by 26 publications

References 23 publications

Measuring Density Profiles of Electrons and Heavy Particles in a Stable Axially Blown Arc

Measuring Density Profiles of Electrons and Heavy Particles in a Stable Axially Blown Arc

Evaluation on current interruption ability of CO2 and SF6 using current and voltage application highly controlled by power semiconductors

Numerical thermofluid simulation of a decaying arc behavior in CO₂/O₂/C₅F₁₀O (C5‐PFK) considering more than nona‐atomic molecules

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Thomson scattering diagnostics of decay processes of Ar/SF6gas-blast arcs confined by a nozzle

Cited by 26 publications

References 23 publications

Measuring Density Profiles of Electrons and Heavy Particles in a Stable Axially Blown Arc

Measuring Density Profiles of Electrons and Heavy Particles in a Stable Axially Blown Arc

Evaluation on current interruption ability of CO2 and SF6 using current and voltage application highly controlled by power semiconductors

Numerical thermofluid simulation of a decaying arc behavior in CO2/O2/C5F10O (C5‐PFK) considering more than nona‐atomic molecules

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Thomson scattering diagnostics of decay processes of Ar/SF₆gas-blast arcs confined by a nozzle

Numerical thermofluid simulation of a decaying arc behavior in CO₂/O₂/C₅F₁₀O (C5‐PFK) considering more than nona‐atomic molecules