Proceedings of Eurotherm78 – Computational Thermal Radiation in Participating Media II 5-7 April 2006, Poitiers, France The influence of carbon monoxide on radiation transfer from a mixture of combustion gases and soot by Vladimir P. SOLOVJOV and Brent W. WEBB Department of Mechanical Engineering, Brigham Young University, Provo, UT 84602, U.S.A. webb@byu.edu Abstract Carbon monoxide and soot may be present in a wide range of concentrations in combustion applica- tions. Generally speaking, high concentrations in both constituents result from locally fuel-rich condi- tions. It is known that soot significantly increases the radiation transfer in combustion applications due to its spectrally continuous emission and high absorption coefficient relative to that of gases. However, it is not generally known how important the contribution from CO is to the overall radiation transfer in the system. The purpose of this work is to investigate the role of CO in the radiation trans- fer from a mixture of combustion gases (H 2 O, CO 2 , CO) with non-gray soot particles in an idealized combustion environment. Calculations of the radiative transfer have been performed for a wide range of possible combinations of the species and soot concentrations and over a wide range of temperatures in order to characterize conditions under which CO is important for accurate prediction of the radiative transfer. Nomenclature I intensity s pathlength N molar density Y concentration C absorption cross-section a gray gas weight F absorption-line blackbody distribution function f v soot volume fraction Greek symbols κ absorption coefficient σ Stefan-Boltzman constant η wavenumber Φ fraction of radiation transfer with or without soot and/or CO Subscripts b blackbody η wavenumber m number of species n number of gray gases 1. Introduction So-called luminous flames contain not only the mixture of combustion gases (principally wa- ter vapor, carbon dioxide and monoxide) but also soot which consists of very small carbon particles [1,2]. The calculation of the radiation field in a luminous flame is more difficult