A comparison between weighted sum of gray gases and statistical narrow-band radiation models for combustion applications

Abstract

The weighted sum of gray gases (WSGG) and the statistical narrow-band (SNB) models are implemented for radiative transfer calculations in realistic combustion gas mixtures and their results are compared. The WSGG model parameters are generated from SNB emissivity calculations in the [300, 2500 K] temperature range for a partial pressure ratio p w p c = 2 . In addition, the same methods are used for the resulution of the transfer equation associated with both models. Comparisons are made for the cases of planar geometry and an axisymmetrical methaneoxygen furnace. When the gas mixture is practically isothermal and surrounded by cold walls, small errors are introduced by the use of the WSGG model. On the other hand, in the case of significant temperature gradients, the inaccurate representation of gas absorptivities by the WSGG model leads to important errors.