Numerically optimized band boundaries of Planck mean absorption coefficients in air plasma

Kloc, Petr; Aubrecht, V.; Bartlova, Milada

doi:10.1088/1361-6463/aa7627

Cited by 6 publications

(8 citation statements)

References 15 publications

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“…One way how to find the optimal band selection is using of numerical optimization. The band selection based on this approach leads to the three-band model [16] with cutting frequencies (see Figs. 1 Even though the frequency limits were found by numerical optimization they correspond also to some important features in the absorption coefficients, namely to the ionization of the nitrogen atom from the basic and the first excited level.…”

Section: P 1 Approximation and Mean Absorption Coefficientsmentioning

confidence: 99%

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Influence of metal vapours on radiation characteristics of air arc plasmas

Bartlova¹,

Kloc²,

Aubrecht³

et al. 2020

PPT

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This paper deals with the evaluation of radiation properties of air arc plasma with various admixtures of Cu, Ag, and Fe, respectively. Under assumption of isothermal plasma cylinder, the net emission coefficients were calculated for various arc radii as a function of the plasma temperature up to 30000K. For plasma with prescribed temperature profile, the equation of radiation transfer was solved in the P1approximation, and the radiation flux and its divergence were calculated.

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Section: P 1 Approximation and Mean Absorption Coefficientsmentioning

confidence: 99%

“…where j denotes the individual frequency bands. The radiative transfer inside the cylindrical plasma column at atmospheric pressure with prescribed temperature profile [16] was calculated using the P 1 approximation. The plasma system consisted of air with various admixtures of Cu, Ag and Fe.…”

Section: P 1 Approximation and Mean Absorption Coefficientsmentioning

confidence: 99%

Influence of metal vapours on radiation characteristics of air arc plasmas

Bartlova¹,

Kloc²,

Aubrecht³

et al. 2020

PPT

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“…Therefore, Kloc et al . have recently studied the optimum value of ℓ for an air plasma at atmospheric pressure, and consequently they proposed that the value of ℓ = 3 R p ( R p is the radius of the plasma column) should be used. However, the optimum value may strongly depend on the shape of plasma column and the gas components as well as on the pressure and temperature conditions.…”

Section: Radiation Transfer Analysis Of Thermal Plasma In Gas Circuitmentioning

confidence: 99%

Review of Thermal Plasma Simulation Technique

Tanaka

Fujino

Iwao

2019

IEEJ Transactions Elec Engng

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The thermal plasma is widely used for power applications such as circuit breakers, welding, cutting, material processing, waste treatment, and recycling. Transient and three-dimensional simulations have recently been conducted, assisting in the understanding of physical phenomena through new developments in computers and calculation methods. In this review, a thermal plasma simulation technique is described. Specifically, the modeling of a new type of inductively coupled thermal plasma, a radiation transfer analysis of thermal plasma in a gas circuit breaker, and plasma movement of arc welding, DC circuit breakers, electric trains, vacuum circuit breakers, and surface treatment affected by an electromagnetic force are described.

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“…no. / Radiative properties of thermal plasmas renormalize the line contribution of the spectral absorption coefficients according to [4] with a characteristic plasma absorption length H = 3 • R p , as suggested in [5]. The plasma radius R p is defined as radius value where the temperature decreased to 50% of the core temperature.…”

Section: Radiative Propertiesmentioning

confidence: 99%

“…To determine the necessary number of bands and location of the band limits in the spectral range, optimization and verification procedures as introduced in [5][6][7] are applied to a specific mixture of C 4 F 7 N and CO 2 . In the optimization procedure two infinitely long cylindrical calculation domains are considered, one with 3 cm and the other one having a 10 cm radius.…”

Section: Radiative Propertiesmentioning

confidence: 99%

Radiative Properties and Numerical Modeling of C4F7N-CO2-O2 Thermal Plasma

Gnybida

Ruempler

Narayanan

2019

PPT

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C4F7N and C4F7N-CO2 mixtures are considered as alternatives to SF6 for use in medium voltage gas insulated switchgear applications (GIS), due to the low global warming potential and good dielectric properties of C4F7N. Current work is focused on the calculation of radiative properties (absorption coefficients) of C4F7N-CO2 thermal plasma and computational fluid dynamics (CFD) simulations of free burning C4F7N-CO2 arcs that are stabilized by natural convection. Absorption coefficients of C4F7N-CO2 plasma used in the CFD model are derived from spectral absorption coefficients by Planck averaging. An optimization procedure has been applied to find the optimal number of spectral bands as well as spectral band interval boundaries. Radiation and flow model results for C4F7N-CO2 in comparison to SF6 and air are provided and discussed.

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Numerically optimized band boundaries of Planck mean absorption coefficients in air plasma

Cited by 6 publications

References 15 publications

Influence of metal vapours on radiation characteristics of air arc plasmas

Influence of metal vapours on radiation characteristics of air arc plasmas

Review of Thermal Plasma Simulation Technique

Radiative Properties and Numerical Modeling of C4F7N-CO2-O2 Thermal Plasma

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