Numerical Investigation Of The Coupled Turbulent Combustion-Radiation In An Axisymmetric Non-Premixed Flame

A turbulent non-premixed methane-air flame was studied in an axisymmetric cylindrical combustion chamber, focusing on thermal radiation effects on temperature and soot concentration fields. The simulation is based on the solution of the mass, energy, momentum and chemical species conservation equations. The turbulence and its interaction with combustion are modelled by the standard k-epsilon model and eddy dissipation concept, respectively. The semiempirical model of Syed is implemented to deal with soot formation and oxidation and thus ensuring the overall efficiency of the present investigation. The radiative heat transfer is surveyed, for two cases: with and without soot radiation. The numerical resolution has been achieved using the Hottel's zonal method and the standard weighted-sum-of-gray-gases model, to predict the real gas-soot mixture radiation effect. A new concept of optical exchange gap has been recently proposed and applied here after avoiding the singularities obviously encountered in the calculation of the direct exchange areas of volume zones self-irradiance. The obtained numerical results are compared to experimental data due to Brookes and Moss. Radiation exchange is found to noticeably affect temperature and soot volume fraction predictions and slightly the mixture fraction solutions. The present paper shows that taking into account turbulent combustion-radiation interactions leads to more accurate results by comparison to available experimental data.