Experimental Studies on Self-Ignition of Hydrogen/Air Supersonic Combustion

Self-ignition tests of a model scramjet combustor were conducted by using parallel sonic injection of gaseous hydrogen from the base of a blade-like strut into a supersonic airstream. The vitiated air was produced by burning H 2, O2, and air to a stagnation temperature of 1000 ‐ 2100 K and a stagnation pressure of 0.8 ‐ 1.6 MPa. The effects of different parameters on the self-ignition limits were analyzed. In addition, the effects of the combustor’ s different wall cone gurations on self-ignition limits were specie cally studied. It was found that the wall cone gurations of the combustor had a signie cant effect on self-ignition limits, which might have variations of 420 ‐ 840 K deg in stagnation temperature; however, the local static temperature in the recirculation zones for different wall cone gurations remained the same at approximately 1100 K. It was found that self-ignition could initiate at the exit of the combustor and this can be considered as a weak self-ignition characteristic.