Large eddy simulation of turbulence-combustion interactions in a stagnation point reverse flow combustor

This study focuses on the interaction between turbulence and combustion in a stagnation point reverse flow (SPRF) combustor. Turbulent activities have been examined with large eddy simulation (LES) technique including k-equation subgrid turbulence modeling. The non-premixed and premixed combustion cases are modeled by using partially stirred reactor (PaSR) combustion model with one-step global reaction chemistry. In the non-premixed operation, a lifted flame is located about the two-thirds of the combustor, while an attached flame is observed for the premixed operation. Results of the complex flow field and combustion dynamics showed that SPRF combustor can operate at low emission conditions. The existence of the shear layer between the coaxial jets resulted with intense mixing, which further increases the efficiency of the combustor. Exhaust gas re-circulation prevented high temperature levels, hence high NOx levels within the combustor. The preliminary thermo-acoustic study showed that noise levels are highly affected by the turbulent production and heat release generation mechanisms. The contribution of the combustion noise to the total noise level is higher in the non-premixed operation as compared to the premixed one.