FLAME-HOLDING CONFIGURATIONS FOR KEROSENE COMBUSTION IN A MACH 1.8 AIR-FLOW

The goal of this study was to determine the stability of the name in a recirculation region formed in a wall cavity with ignition provided b y hydrogen injected in the base of the cavity and injection of kerosen e upstream in the boundary layer formed along the wall leading to the cavity. The experimental conditions, i.e., Mach 1.8 and air stagnation temperatures to 1000 K, correspond to the beginning of the hypersonic flight regime also referred to as cold start conditions. The hydrogen and the preinjected kerosene flow rates were modulated during the tes ts and temperature probes placed in the cavity indicated their effect on the local equivalence ratio. Preinjection of kerosene reduced the l ocal equivalence ratio at low air stagnation temperature by increasing the entrainment of fresh air into the recirculation region. At high t emperatures the additional fuel brought by the presence of kerosene ha d a detrimental effect on the stability of the flame in the cavity.