Large eddy simulation of reacting flows applied to bluff body stabilized flames

The objective of this paper is to present a large eddy simulation model for chemically reacting flows. The large eddy simulation model, founded on a physical model based on modern continuum mechanics, includes a complete treatment of the subgrid stresses and fluxes including both backscatter and diffusion. To investigate the predictive capabilities of the large eddy simulation model, numerical simulations of a configuration corresponding to a rig consisting of a rectilinear channel with a triangular-shaped bluff body have been performed. Both nonreacting and reacting flows have been examined under a variety of operating conditions. This paper focuses on the reacting case, which is characterized as lean and premixed. The simulation results are compared to experimental measurements of temperature, constituent mass fraction, and velocity fields in the test rig. The results indicate that the large eddy simulation technique works well and mimics most of the significant flow features, including the typical unsteady flow structures. The results from the large eddy simulations are furthermore used to investigate the mechanisms responsible for the typical flowfield in a bluff body stabilized flame.