Radiation emission coefficients for sulfur hexafluoride arc plasmas

Liebermann, R. W.; Lowke, J. J.

doi:10.1016/0022-4073(76)90067-4

Cited by 197 publications

(134 citation statements)

References 15 publications

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“…This method is of interest because the complicated calculation of the net emission (net meaning emission minus absorption, which is mathematically represented by the divergence of the radiative flux) integrated over all the spectrum (VUV, UV, visible and IR parts) is previously calculated for isothermal conditions and then injected in the energy conservation equation by a simple source term. This NEC was initially proposed by Lowke [1] and first calculated for SF 6 by Liebermann and Lowke [2]. Since this pioneer work, other teams have been calculating the NEC for SF 6 [3][4] and several works demonstrated the interest in and accuracy of this coefficient for calculating the temperature field in arcs [5] introducing a multiplying factor [6][7].…”

Section: -Introductionmentioning

confidence: 99%

Improvements of radiative transfer calculation for SF₆ thermal plasmas

Randrianandraina

Cressault

Gleizes

2011

J. Phys. D: Appl. Phys.

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We present a comparison between an exact calculation of radiative transfer in SF6 thermal plasma based on a fine description of the spectrum with 300 000 spectral points for each temperature value, for simplified conditions (1D and 2D geometries with imposed symmetrical temperature profiles and local thermodynamic equilibrium) and two kinds of approximated calculations. The first is the classical net emission coefficient largely used in arc modelling. The second one is based on a very simplified spectral description with only seven intervals assuming a grey body condition within each interval and using the Planck and the Rosseland averaging for deducing the mean absorption coefficient (MAC). At high temperature the use of the Rosseland averaging is not satisfactory. The other two approximated methods (net emission and the Planck averaging) are acceptable but the radiative flux is in general not very accurate. The radiative transfer calculation can be improved following three ways: a better knowledge of the basic processes and in particular of the absorption coefficients for diatomic and polyatomic molecules, the use of different definitions of MACs (Planck averaging at high temperature and mean natural value at low temperature) and a careful choice of the spectral intervals.

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Section: -Introductionmentioning

confidence: 99%

Improvements of radiative transfer calculation for SF₆ thermal plasmas

Randrianandraina

Cressault

Gleizes

2011

J. Phys. D: Appl. Phys.

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“…This closely represents the MAC approximation, however it is not the most accurate approximation of the continuum radiation which is usually used for the selection of MAC band boundaries [14]. The more accurate description was provided by Liebermann and Lowke [15], suggesting the absorption decays with a factor of 1=m 3 from some absorption edge value.…”

Section: Testmentioning

confidence: 99%

On the Selection of Integration Intervals for the Calculation of Mean Absorption Coefficients

Kloc

Aubrecht

Bartlova

et al. 2015

Plasma Chem Plasma Process

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In radiation modeling of thermal plasmas non-grey models are applied where the radiative transport is described in several frequency bands (spectral intervals). Hereby mean absorption coefficients have to be calculated by a spectral integration procedure, providing a constant mean absorption coefficient for each band. Depending on the number of bands, one or more integration boundaries have to be selected in order to do the integration. In this paper we evaluate the influence of the selection of these integration boundaries on the mean absorption coefficient and the also radiation transfer by applying the mean absorption coefficients in a radiation transport model. Using a simplified twoband model we demonstrate that the selection of the integration boundary has a large impact on the total model accuracy. We show that in some cases selecting a band boundary right at the frequency where the continuum absorption shows a jump can introduce a significant error into the radiation calculation. The process of the integration interval selection thus demands a global optimization procedure to properly evaluate the boundaries of each frequency band.

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“…Because a free electron can assume non-quantized kinetic energies, its recombination with an ion will result in continuum radiation. The excess energy of an electron with velocity v e is converted into radiation according to the relation: The photo-ionization cross sections for neutral atoms were calculated by the quantum defect method of Burgess and Seaton [7], the cross sections of photo-ionization of ions were treated using the Coulomb approximation for hydrogen-like species [8].…”

Section: Absorption Properties Of Plasmamentioning

confidence: 99%

“…Semi-empirical formulas given in [8,9] were used. The line shapes were calculated by convolution of Gaussian and Lorentzian profiles, resulting in a Voigt profile.…”

Section: Absorption Properties Of Plasmamentioning

confidence: 99%

P1-approximation for radiative transfer: application to SF₆ + Cu arc plasmas

et al. 2014

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Abstract:The objective of the paper consists of a theoretical prediction of radiative heat transfer in arc plasmas of SF 6 (sulphur hexafluoride) with various admixtures of copper vapours. The P1-approximation was used as a mathematical tool. Due to the very complicated frequency dependence of absorption coefficients, the Planck and Rosseland mean absorption coefficients have been derived from the calculated absorption spectrum. The main radiation quantities (radiation intensity, radiation flux density and its divergence -net emission) have been determined in cylindrical arc plasmas for several model temperature profiles. Contribution to the net emission of copper admixtures is discussed. Conclusions have been made concerning validity and utilization of various absorption means.

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Radiation emission coefficients for sulfur hexafluoride arc plasmas

Cited by 197 publications

References 15 publications

Improvements of radiative transfer calculation for SF₆ thermal plasmas

Improvements of radiative transfer calculation for SF₆ thermal plasmas

On the Selection of Integration Intervals for the Calculation of Mean Absorption Coefficients

P1-approximation for radiative transfer: application to SF₆ + Cu arc plasmas

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Radiation emission coefficients for sulfur hexafluoride arc plasmas

Cited by 197 publications

References 15 publications

Improvements of radiative transfer calculation for SF6 thermal plasmas

Improvements of radiative transfer calculation for SF6 thermal plasmas

On the Selection of Integration Intervals for the Calculation of Mean Absorption Coefficients

P1-approximation for radiative transfer: application to SF6 + Cu arc plasmas

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Product

Resources

About

Improvements of radiative transfer calculation for SF₆ thermal plasmas

Improvements of radiative transfer calculation for SF₆ thermal plasmas

P1-approximation for radiative transfer: application to SF₆ + Cu arc plasmas