Characterization of the coherent structures in swirling flames stabilized in a two-staged multi-injection burner: influence of the staging factor.

National audienceStaged multi-injection combustors seem good candidates to face flame stabilization problems (combustion instabilities, flashback, flame extinction), encountered in lean premixed prevaporized (LPP) burners. Staging procedures enable fuel distribution control while multipoint injection can lead to a fast and efficient mixing. In the present study, a laboratory-scale staged multipoint combustor is characterized using High Speed Particle Image Velocimetry and Planar Laser Induced Fluorescence measurements. It is shown that the fuel distribution strongly affects the flame stabilization processes, leading to a more or less strong thermo-acoustic instability. Furthermore, results reveal the presence of a precessing vortex core (PVC), that may lead to a better flame stabilization