Implementation of LES/SFMDF for Prediction of Non-premixed Turbulent Flames

by Drozda, Tomasz Grzegorz

Large eddy simulation (LES) is conducted of two experimental flame configurations. The first is the flame studied in the experiments of the Combustion Research Facility at the Sandia National Laboratories (SNL) and the Technische Universitat Darmstadt (TUD), namely Flame D. This is a turbulent piloted non-premixed methane jet flame. The second flame is also studied by the Combustion Research Facility at the Sandia National Laboratories and at the Thermal Research Group at the University of Sydney. This is a turbulent bluff-body stabilized hydrogen-methane jet flame. The subgrid scale (SGS) closure in LES is based on the scalar filtered mass density function (SFMDF) methodology. The SFMDF is the mass weighted probability density function (PDF) of the SGS scalar quantities. A flamelet model is used to relate the scalar composition to the mixture fraction. The modeled SFMDF transport equation is solved by a hybrid finite-difference (FD) / Monte Carlo (MC) scheme. This is the first LES of realistic turbulent flames using the transported PDF method as the SGS closure. The results via this method capture some of the important features of the flames as observed experimentally.