EVALUATION OF THE INFLUENCE OF FLUIDIC CONTROL ON AIR FLOW DISTRIBUTION AND FUEL SPLIT VARIATION OF A STAGED LEAN JET ENGINE BURNER AT IDLE AND CRUISE CONDITION

Kurzfassung

In a cooperation of DLR and JAXA, a staged jet engine burner has been investigated, which is a derivate of the JAXA TechCLEAN burner. It is equipped with a fluidic diverter allowing variation of the air distribution between pilot and main stage. The reacting flowfield issuing from the burner has been investigated with and without fuel and fluidic air staging in an optically accessible single sector combustor at medium pressure using Laser-spectroscopic methods at conditions related to idle and cruise. The results show that the fluidic device influences the flow field directly by shifting the air and thereby zonal stoichiometry, and indirectly by modification of the piloting effect on local stabilization and combustion intensity. The latter effect can be the stronger one, since those changes can lead to amplification caused by the nonlinear dependence of heat release on local mixture fraction. With air flow splits and fuel schedule properly scaled, this can be used to extend the range of stable and efficient operation by a greater margin than would be expected from the amount of shifted air alone.