Modeling Combustion in a Rearward-Facing Step Using a Hybrid RANS/LES Method

Abstract

Abstract With incremental High-Performance Computing (HPC) scalability and performance improvements, hybrid Reynolds Averaged Navier Stokes (RANS)/Large Eddy Simulation (LES) have become popular for modeling reactive flow configurations. Hybrid RANS/LES methods like Stress-Blended Eddy Simulation (SBES) are presented in this paper and have been applied to model near-wall flows using two-equation k-ω RANS formulation while switching to LES in the separated flow region using a blending function. Turbulent combustion in a rearward-facing step is modeled by using Flamelet Generated Manifold (FGM) with SBES turbulence. A turbulent premixed propane/air flame (φ = 0.57) is stabilized in the turbulent mixing layer (ReH = 22, 100) formed at the rearward-facing step. The results obtained show a good agreement with the experimental data for velocity, temperature and species mass fractions at various locations in the channel.