COMPARISON OF ENGINEERING MODELS OF NONGRAY BEHAVIOR OF COMBUSTION PRODUCTS

Abstract

Various engineering models of nongray behavior of combustion products are compared with one another for two types of sample problem. The Curtis-Godson approximation method and the weighted-sum-of-gray-gases-model (WSGGM) are used to compute the emission from a Lorentz line in a non-isothermal path, as the first problem. The Milne-Eddington type WSGGM underestimates the effective line width. Secondly, the gray gas model, the WSGGM and the spectral group model (SGM, a modification of WSGGM) are used to solve one-dimensional inhomogeneous slab problems and are compared with the nongray wide band results. The results from both the WSGGM and the SGM are in good agreement with the reference. The result from the gray gas model is significantly away from those of the other models.