Steady-State Simulation of a Methane-Air Partially Premixed Turbulent Flame

Two steady-state simulations of a benchmark (Sandia Flame D) methane-air, turbulent, partially premixed flame are compared. The first uses an equilibrium mixture fraction model for the thermo-chemistry, while the second uses a steady, strained laminar-flamelet model. These non-premixed combustion models are coupled with a premixed reaction progress model to simulate a partially premixed jet flame. The laminar-flamelet approach predicts CO and H2 more accurately than the equilibrium model by accounting for the unbumt premixed stream within individual flamelets, and improved radical (such as OH) predictions by incorporating non-equilibrium chemistry effects due aerodynamic strain (fluid shear).