Japan Aerospace Exploration Agency Computational Science Research Group, Institute of Aerospace Technology
Japan Aerospace Exploration Agency Computational Science Research Group, Institute of Aerospace Technology
Japan Aerospace Exploration Agency Computational Science Research Group, Institute of Aerospace Technology
Japan Aerospace Exploration Agency Computational Science Research Group, Institute of Aerospace Technology
In this study, flame dynamics of secondary fuel injection control is investigated by Large Eddy Simulation (LES) in a lean premixed combustor to elucidate the oscillation suppression phenomenon observed in the previous experiment. Without secondary fuel injection, large amplitude longitudinal oscillations were observed. With constant injection of secondary fuel, the oscillation amplitude reduced and with harmonic feedback injection, it further reduced. In this process, the flame shape and the flame behavior were changed. To understand the flame dynamics, large eddy simulations are carried out. The LES results show that the oscillation reduction is attributed to the roles of both main flame and secondary flame. The interaction of the main flame and vortices is reduced when the injection is on, thus heat fluctuation is reduced. The secondary flame helps the flame base stabilization and directly modulates the heat release in the case of feedback injection. The phase relations between the pressure, secondary heat release and injection velocity are also shown here. With these effects combined, the oscillations are suppressed. The present study indicates that the LES can be a tool to understand flame dynamics with control.