Advances in Modeling Radiative Transport in High Temperature Gases

Thermal radiation heat transfer figures prominently in combustion systems. In perhaps all of these applications the impact of the transport on the environment is clear. Depletion of non-renewable energy resources is a concern. Industrial combustion utilization is under increasing pressure to reduce the exhaust pollutant emissions. The generation of pollutants in a flame is clearly dependent on the temperature history of the related chemical species. Therefore, treatment of the radiation transfer becomes critical not only to the accurate determination of the fluxes to the load, but also the prediction of local temperatures in the flame with the attendant impact on pollutant formation. Treatment of radiative transport from the gas phase in a combustion system is particularly challenging due to the strong spectral variation of the gas radiative properties (absorption coefficient, K_η. The absorption spectra of gases consist of many thousands of spectral lines because gases emit and absorb electromagnetic radiation only at discrete frequencies where the corresponding photon energies match the quantum changes in energy of the gas molecules.