Operational Sensitivities of an Integrated Scramjet Ignition/Fuel-Injection System

Results are presented of experiments conducted in a supersonic wind tunnel on an integrated fuelinjection/ignition system, consisting of an aeroramp injector and a plasma-torch igniter. The main goals of the work were to determine how the lifting effect of the aeroramp affected the plasma jet, to ascertain how the injection of fuel through the aeroramp and the power supplied to the torch ine uenced the distributions of excited species downstream of the device, and to investigate any synergistic effects from the combination. The aeroramp was observed to have a strong lifting effect on the plasma jet, especially for injector momentum-e ux ratios above 1.5. In addition, increases in the torch input power produced an exponential effect on the emission intensity of the excited-state species downstream of the plasma jet, but was not observed to ine uence the jet penetration height. The results demonstrate that the increased penetration of combustion enhancing radicals is largely a function of the e uidic mechanisms generated by the injector and, thus, aids the plasma torch in ine uencing the combustion kinetics farther into the freestream than would normally be possible.