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FLAME WRINKLING FACTOR DYNAMIC MODELING FOR LARGE EDDY SIMULATIONS OF TURBULENT PREMIXED COMBUSTION

Thomas Schmitt
Laboratoire EM2C CNRS - Ecole Centrale Paris Grande Voie des Vignes, 92295, Chatenay-Malabry, France

Matthieu Boileau
Laboratoire EM2C CNRS - Ecole Centrale Paris Grande Voie des Vignes, 92295, Chatenay-Malabry, France

Denis Veynante
Ecole Centrale Paris CNRS, UPR 288, Laboratoire EM2C Grande Voie des Vignes 92290 Chatenay-Malabry, France

Vincent Moureau
CORIA CNRS - INSA et Universite de Rouen Site du Madrillet - BP 8 76801 Saint Etienne du Rouvray, France

Abstract

Large eddy simulations (LES) of a turbulent jet premixed flame are performed using a dynamic formulation for the flame surface wrinkling factor entering the F-TACLES model. The model parameter is automatically adjusted on the fly, taking advantage of the knowledge of the resolved scales in the flow field. Two cases are considered: a global formulation where the parameter is spatially uniform and depends only on time and a local determination where this parameter varies with both location and time.
The global formulation, in which the model parameter evolves only slightly around its mean value, provides similar results than with a fixed, but adjusted, value. On the other hand, a local parameter is found to increase from low values, corresponding to planar laminar flame fronts, to values larger than in the global case, as the flame is progressively wrinkled by turbulence motions when convected downstream. Moreover, when the flame is submitted to velocity modulations, parameter values, as well as local heat release rates, are clearly related to the large coherent structures developing in the flow, in agreement with previous observations. Then a local dynamic model formulation might play an important role to predict combustion instabilities.