Large Eddy Simulation of Supersonic Combustion in a Cavity-Strut Flameholder

Large Eddy Simulation (LES) of supersonic combustion in a cavity-based flameholder in an experimental test facility is carried out. Nonreacting and reacting flow analysis is performed within the compressible LES framework using Linear Eddy Mixing (LEM) model as a subgrid closure for turbulent combustion (LEMLES). Preliminary results of an artificial neural network (ANN) based filtered chemical rates modeling (Turbulent-ANN) are also presented. Two configurations: a baseline cavity with 11 injectors on the aft ramp and a cavity with a strut positioned upstream of the cavity with 6 fuel injectors are analyzed. Numerical data are in good agreement with the velocity measurements obtained using Hydroxyl Tagging Velocimetry (HTV) in nonreacting flow. Results show that the multiple shear layers in the wake of the strut provide a wider mixing region that has the potential for flame stabilization. Low pressure region behind the strut causes increased mass transfer between cavity and main flow stream. Reacting flow computations using LEMLES and Turbulent-ANN approach show good agreement with available wall pressure data. LEMLES simulates the small scale subgrid processes whereas the Turbulent-ANN methodology can predict same flame physics in a computationally much affordable way.