Near field flow structure of isothermal swirling flows and reacting non-premixed swirling flames

摘要: Two confined lean non-premixed swirl-stabilized flame typologies were investigated in order to achieve detailed information on the thermal and aerodynamic field close vicinity of burner throat provide correlation with exhaust emissions. Previous finding indicated generation a partially premixed radial fuel injection purely diffusive co-axial swirling co-flow. In present work, experimental study is reported which has been conducted straight exit laboratory no quarl cone, fuelled by natural gas air, fired vertically upwards stabilized at end two concentric pipes annulus supplying swirled air central pipe delivering fuel. typologies, (i.e., transverse), leading different mixing mechanisms, have characterized through techniques: particle image velocimetry (PIV) laser Doppler (LDV) for comprehensive analysis velocity field, still photography detection front main visible features, thermocouples temperature distribution. Isothermal flow conditions included investigation basic picture comprehend modifications induced combustion process. The results that, although global process structure are governed swirl motion imparted stream, methodologies play an important role mixture formation stabilization primary zone. Particularly, it found case axial injection, turbulent interaction between jet backflow generated can induce intermittent penetration recirculated hot products sooting luminous plume, phenomenon totally absent injection.