On the blow‐off correlation for swirl‐stabilised flames with a precessing vortex core

Large eddy simulations of turbulent swirl-stabilised flames gradually approaching blow-off conditions in a gas turbine model combustor are undertaken. The global equivalence ratio the is reduced by increasing and decreasing air fuel flow rates respectively. filtered reaction rate for partially premixed combustion modelled using presumed joint probability density function flamelet model. average position flame closer to nozzle when decreased, contrary what expected. Comparisons made with simultaneous particle image velocimetry , acetone OH planar laser induced fluorescence imaging corresponding simulated case. It demonstrated that mechanisms leading local extinction well captured simulation insufficient mixing precessing vortex core leads extinction. Further analysis shows including heat loss effects within modelling important near or blow-off. non-adiabatic influences re-stabilisation after lift-off edge follows rotation PVC. A correlation based on Damköhler number proposed PVC frequency chemical time scale. Analysis respond flamelets