Predictive accuracy of discrete ordinates method (DOM) was assessed by applying it to the prediction of incident radiative fluxes on the walls of a gas turbine combustor simulator (GTCS) and comparing its predictions with measurements. Input data utilized for the DOM were measured gas concentration and temperature profiles and inner wall temperatures of the GTCS which is a cylindrical enclosure containing a turbulent diffusion flame of propane and air. Effects of order of approximation (S-4 and S-6) and using uniform and non-uniform gas absorption coefficients for the non-homogeneous medium on the accuracy of the predicted heat fluxes were also investigated. Comparisons show that S-4 approximation is adequate for the prediction of incident wall heat fluxes and that the use of an absorption coefficient profile based on measured gas concentrations and temperatures improves the accuracy significantly. (C) 2000 Elsevier Science Inc. All rights reserved.