Large-Eddy Simulation of a Turbulent Lifted Flame in a Vitiated Co-Flow
نویسندگان
چکیده
Large-eddy simulation (LES) of a lifted flame in a vitiated co-flow has been performed using an unsteady flamelet/progress variable (UFPV) model. This model is an extension to the steady flamelet/progress variable approach, and describes the transient autoignition process of the lifted flame through the unsteady flamelet model. The particular advantage of this model is that it eliminates the flamelet time scale, and all thermochemical quantities are parameterized by mixture fraction, reaction progress parameter, and stoichiometric scalar dissipation rate. For application to LES, a presumed probability density function closure is employed, in which a beta-distribution is used for the mixture fraction, a statistically most-likely distribution is employed for the reaction progress parameter, and the distribution of the stoichiometric scalar dissipation rate is modeled by a Dirac delta function. Compared to the steady flamelet/progress variable model, predictions from the UFPV model show significant improvements, and the spatial evolution of the flame ignition process and lift-off height is in good agreement with experimental data. Flow field structure, statistical results, and scatter data are compared with experimental data, and potential improvements of the model are discussed.
منابع مشابه
Large Eddy Simulation of a Turbulent Lifted Flame via Rate-Controlled Constrained Equilibrium
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