A comparative study of gray and non-gray methods of computing gas absorption coefficients and its effect on the numberical predictions of oxy-fuel combustion

Computational Fluid Dynamics (CFD) simulations are performed to model the radiation process in natural gas fired furnaces using different gray and non-gray radiation models. Simulations of two representative furnace cases (HTAC and OXYFLAM) were performed and the computed radiative fluxes compared with measurements when available. The nearly homogeneous and isothermal conditions encountered within the furnace did not result in any significant differences in the predicted incident radiative flux profiles between the gray and non-gray models. However, differences between the gray and non-gray radiation calculations manifested itself through the temperature distributions away from the burner region.