Performance of Pylons Upstream of a Cavity-Based Flameholder in Non- Reacting Supersonic Flow (POSTPRINT)

摘要

Cavity-based fuel injection and flame holding, typically found in hydrocarbon-fueled scramjet applications, are of current interest for use in supersonic combustors. Both the Air Force Research Lab (AFRL) and the Air Force Institute of Technology (AFIT) at Wright- Patterson Air Force Base in Ohio are investigating the enhancement of fuel-air mixing with small pylons that project into the supersonic flow upstream of a flame holder cavity. The pylons were of three sizes (medium, tall, and wide) and shaped as a thin triangular wedge with a 30-degree inclination angle. The goal was to measure the mixing efficiency and shock loss of each pylon setup for comparison to the baseline condition of transverse injection without pylons. Non-reacting flow was measured using intrusive and non intrusive techniques to obtain pitot pressure, total temperature, cone-static pressure and laser induced Raman spectroscopy to determine species concentration over the cavity downstream of the injection port. Results demonstrated that pylons increase fuel penetration, while not adding significantly to shock losses or overall mixing compared to baseline.