Date of Award


Document Type


Degree Name

Master of Science in Aeronautical Engineering


Department of Aeronautics and Astronautics

First Advisor

Richard D. Branam, PhD


The difficulties with fueling of supersonic combustion ramjet engines with hydrocarbon based fuels presents many challenges that are currently being tackled by the Air Force Research Lab Propulsion Directorate Aerospace Propulsion Division. As the scramjet engine designs are scaled up, the need for a better solution to supersonic mixing has led to the development of many different styles of fuel injection. An aerodynamic ramp injector has been shown to have a quantitative improvement over a physical ramp while still achieving desirable mixing characteristics. The objectives for this research was quantifying the performance and operability implications of replacing four 15 degree round injectors with four arrays of improved aeroramp injectors. Ignition limits and pre-combustion shock position were used to define the operability differences while combustion efficiency was the primary metric used for performance comparisons. Performance and operability data was derived from data taken determining the ignition limits, the wall static pressures, temperature measurements, and thrust stand loading. It was determined that the operability reduces significantly for the aeroramp injector, but the performance is virtually identical to the round injectors. The aeroramp injector indicated improved near-field combustion indicating the potential for better performance in higher Mach number flow to include full scramjet mode.

AFIT Designator


DTIC Accession Number