Flame Extinction Dynamics of Lean Premixed Bluff-Body Stabilized Flames
There is a crucial need to improve energy conversion efficiencies and minimize the environmental impact of turbulent combustion systems for energy production. Lean premixed turbulent combustion operation will significantly reduce efficiency-based thermal losses and combustion emissions. However, the performance of lean turbulent combustion technology is inevitably limited by the effects of flame extinction. Flames operating at lean conditions are susceptible to stabilization dynamics caused by local reaction extinction; this leads to global flame blowout and termination of the combustion energy production process. An improved understanding and prediction of flame extinction and stability will guide strategies to enhance efficiency, reduce emissions and improve performance of turbulent combustion systems. This research is focused on understanding the physical mechanisms of flame extinction using a newly-developed physics-based model. The novelty of this model is that it interactively couples the physics of the turbulent flow through a dynamic Lagrangian vortex method and the strained flame reaction kinetics using a one-dimensional opposed-jet flame. This innovative modeling strategy effectively captures the dynamic flame stability and extinction for turbulent premixed combustion.