EXPERIMENTAL STUDIES ON SELF-IGNITION OF HYDROGEN AIR SUPERSONIC COMBUSTION/

Self-ignition tests of a model scramjet combustor were conducted by us ing parallel sonic injection of gaseous hydrogen from the base of a bl ade-like strut into a supersonic airstream, The vitiated air was produ ced by burning H-2, O-2, and air to a stagnation temperature of 1000-2 100 K and a stagnation pressure of 0.8-1.6 MPa, The effects of differe nt parameters on the self-ignition limits were analyzed, In addition, the effects of the combustor's different wall configurations on self-i gnition limits were specifically studied. It was found that the wall c onfigurations of the combustor had a significant effect on self-igniti on limits, which might have variations of 420-840 K deg in stagnation temperature; however, the local static temperature in the recirculatio n zones for different wall configurations remained the same at approxi mately 1100 K, It was found that self-ignition could initiate at the e xit of the combustor and this can be considered as a weak self-ignitio n characteristic.