Les of partially-premixed unsteady combustion

Large-Eddy Simulation (LES) methodology has been used to model the combustion dynamics in a realistic swirl-stabilized dump combustor. A novel partially-premixed flamelet combustion model is employed to capture the interaction of the unsteady flame-front with local velocity and equivalence ratio fluctuations. Two sets of simulations have been conducted which employ this combustion model. First, the model is used to simulate temporal variations in the mean inlet fuel flow-rate mimicking pressure and fuel feed-line interaction, a major source of instabilities. The second application models the effects of unmixedness as a result of spatial various in the inlet equivalence ratio. A baseline, uniform equivalence ratio simulation is also reported and is used for comparison. It is shown that the present model is capable of capturing the combustion dynamics under both temporal and spatial fluctuations in the equivalence ratio.