To reduce the computational effort in 3D CFD simulations, a common practice is to parameterize and tabulate a priori the scalar evolution of a reactive turbulent environment by few variables that govern the scalar evolution in a laminar flame. Two famous methodologies that use this approach are the Flamelet Generated Manifold (FGM) and the Flamelet Progress Variable (FPV) models. Both FPV and FGM parameterize all species and temperature by a mixture-fraction (Z) and a progress variable or progress parameter (C). However, the two models treat the flamelet manifold between equilibrium and flame extinction in a different manner. The Stanford FPV model solves flamelet equations in the (unstable) middle and lower branches of the flamelet S-curve, while the FGM (Fluent approach) model solves an unsteady extinguishing flamelet from the last stable burned steady solution before extinction. The generated tables for FGM and FPV show similar behavior in the mixture fraction space but different behavior on the progress variable space. Where the FPV solutions, show an extinction curve where the progress variable and temperature are decreasing with increasing the mixture fraction. Both models are compared here with experimentally measured thermo-chemical states for Sandia turbulent jet diffusion flames C and F. The results show that under lean and stoichiometric conditions (Z< Zstoic) both models show similar behavior, with slightly better sample from the FPV model for ultra-lean mixture, and better behavior for the FGM model in the stoichiometric range. However, on the higher rich mixture fraction values FPV shows better predictions for the CO mass fraction and the temperature field than the FPV.
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