Effective plasma radius for Planck mean absorption coefficient

conference paper

English

Numerical simulation of radiation transfer in a complex geometry is a very computationally demanding process requiring tremendous amount of computational power. One way to reduce the computational power requirements is replacing the fully spectrally resolved absorption coefficient with just a few spectral bands holding a mean value of the absorption coefficient. The challenge is to calculate the band distribution and the mean value in each band in a way that the induced error on the radiation transfer is as small as possible. In this contribution we present evaluation of effective plasma radius needed to properly calculate the Planck mean absorption coefficient. This definition of the mean absorption coefficient tends to overestimate the importance of the atomic lines. Therefore corrections to the line intensity are needed which in turn require knowledge of the effective plasma radius. The evaluation was carried out by calculation of radiation transfer inside cylindrical air plasma with known temperature profile and pressure of one bar. Three distinct temperature profiles were used to approximately emulate different types of arcs. The results indicate that it is possible to find the best effective plasma radius especially if the entire evaluation process is coupled with numerical optimization. It is possible to reach a good accuracy of an arc plasma radiation transfer calculation with the usage of the mean absorption coefficients.

Radiative heat transfer, mean absorption coefficients, electric arc, plasma

KLOC, P.; AUBRECHT, V.; BARTLOVÁ, M.

11. 9. 2016

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