A COMPARISON OF FLAMELET MODELS FOR PREMIXED TURBULENT COMBUSTION

Five flamelet models for premixed turbulent combustion are described and compared in the case of a one-dimensional turbulent flame propagating in frozen turbulence. This simple configuration allows ananalytical solution (KPP) to be obtained as devised by Kolmogorov, Petrovski, and Piskunov and performed by Hakberg and Gosman [1]. The explicit solution obtained by this analysis provides the turbulent flame speed as a function of the model parameters and of the turbulence characteristics. These results are compared with experimental data of Abdel-Gayed et al. [2] and with results obtained with the classical eddy break-up model. The realizability of the models is also studied. Recent models based on direct numerical simulation results correctly predict the ''bending'' of the turbulent burning velocity U(T) as a function of the RMS turbulent velocity u' as well as the total quenching of the flame in sufficiently intense turbulence. It is shown that this bending effect may be obtained without taking into account strain effects on the laminar burning velocity. However, no model is able to reproduce all data of Abdel-Gayed and Bradley in a satisfactory way. The reasons for these discrepancies are discussed.