Dynamics character of swirling flame investigated by OH and CH2O planar laser-induced fluorescence

摘要

The model combustor of aircraft engine under fuel-lean condition is characterized by planar laser-induced fluorescence(PLIF) technique. By imaging the fluorescence from OH and CH_2O simultaneously under various operation points, thetransient structures of the reaction zone and preheat zone have been investigated. By the application of proper orthogonaldecomposition (POD) and extended POD (EPOD) methods to the OH PLIF and CH_2O PLIF data, the main dynamicsmodes of the swirling flame are extracted, as well as the CH_2O PLIF signal distribution for each POD mode. Theexperimental results indicate that as the thermal power of the combustor increases, the time-averaged structure anddynamics modes experience notable transitions. At relatively high flow rate, local extinction occurs and unburnt fuelemerges in the external recirculation zone (ERZ).