Scalar Filtered Density Function for Large Eddy Simulation of a Bunsen Burner

The scalar filtered density function methodology is employed for large eddy simulation of a turbulent stoichiometric premixed methane-air flame. The scalar filtered density function accounts for the subgrid-scale chemical reaction by considering the mass-weighted probability density function of the subgrid-scale scalar quantities. A transport equation is derived for the scalar filtered density function in which the effects of chemical reactions appear in closed form. The subgrid-scale mixing is modeled via the linear mean square estimation model, and the convective fluxes are modeled via a subgrid-scale viscosity. The modeled scalar filtered density function transport equation is solved by a hybrid finite difference and Monte Carlo scheme. A novel irregular Monte Carlo portioning procedure is developed that facilitates efficient simulations with realistic flow parameters. Combustion chemistry is modeled via five-step, nine-species reduced chemical kinetics. Simulated results are assessed by comparisons against laboratory data. Good agreements are observed, capturing several important features of the flame as observed experimentally.