Numerical predictions of a turbulent diffusion flame in a cylindrical combustor using eddy dissipation and flamelet combustion models

Abstract

A mathematical model has been applied to simulate a confined, turbulent natural gas diffusion flame for which measurements were reported in the literature [7]. The combustion is modelled using both eddy dissipation [2] and non-equilibrium, mixedness—reactedness flamelet [6, 20] models. The latter model is based on a laminar flamelet approach originally developed for premixed combustion. The turbulence is represented by a Reynolds stress model based on the differential transport equations for stresses. The computational results are compared with experimental data for gas temperature and species concentrations. The predictions obtained using the flamelet model are found to be in good agreement with measurements, whereas the eddy dissipation combustion model fails to capture the measured trends in the near-burner region. Efforts have been made to improve the quality of the predictions of the latter model by incorporating an extinction criterion [25] and by adjusting the value of the model parameter. Both actions generate predictions similar to that of the flamelet model.