A Dynamic SGS Model for LES of Turbulent Premixed Flames

Numerical simulations are carried out for transient turbulent premixed flames using large eddy simulations (LES) technique. The sub-grid scale (SGS) mean chemical reaction rate is calculated using a simple algebraic relation for flame surface density (FSD), with a dynamic formulation for the model coefficient. The dynamic model is derived based on fractal theory and flame wrinkling factor, which is implemented in the in-house compressible LES code. The developed model is used to simulate turbulent premixed flames of stoichiometric propane/air mixture in a vented combustion chamber, propagating over built-in solid obstacles. The fractal dimension is dynamically calculated by viewing the flame front as fractal surface, using the SGS velocity fluctuations and the strained laminar burning velocity. The model predictions are validated against experimental measurements where good agreements are obtained.