Optimal Band Selection for the Calculation of Planck Mean Absorption Coefficients

Abstract

Abstract. Radiative heat transfer is a major heat loss mechanism in thermal plasmas generated during arc flashes/faults in switchgear applications or during high current interruption in low voltage circuit breakers. A common way to calculate the radiation balance is by means of approximate non-gray radiation models like P1 or discrete ordinates (DOM), where the frequency dependent absorption and emission are described in a number of frequency intervals (bands) using a constant absorption coefficient in each band. Current work is focused on finding the optimal number of bands as well as band interval boundaries that provide a reasonable level of accuracy in comparison to a full spectral solution. An optimization procedure has been applied to different SF 6 and copper vapor gas mixtures for an assumed temperature profile. Radiation model results using optimized band averaged absorption coefficients as well as spectral values are provided and discussed for the exemplary temperature profile.

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

“…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.…”