Investigation Of Ignition And Flameholding Of Cavity Flameholders In Supersonic Flowfields

Flame holding technique of supersonic combustion based on cavity is studied in this paper, experiment and numerical simulation is carried out to investigate flow and combustion process in cavity flame holder.Acetone Planar Laser Induced Fluorescence (Acetone-PLIF) and CFD method were employed to study the process of the helium jet adulterated with acetone vapor transported into cavity in non-reaction flows. Results show that the form of the cavity's shear layer is influenced by jet, and changes with the distance between the jet and the front wall of cavity. If the shear layer of cavity is planar, the jet can hardly enter the cavity.High-speed photography, OH-PLIF and CFD method were employed to study the process of ignition and flame holding of acetylene and H2 jet in cavity. Results indicate that flame originates from the front wall of cavity, and forms different combustion areas based on the jet location and equivalence ratio. The flame can be divided into three forms based on the shape of combustion areas and the pressure distribution in the supersonic combustor. The ignition points of different gas fuels are different, but the mechanism of cavity flame holding is same.