Date of Award
Master of Science
Department of Aeronautics and Astronautics
Paul I. King, PhD
Pulse detonation engines (PDE) rely on rapid ignition and formation of detonation waves. Because hydrocarbon fuels are composed typically of long carbon chains that must be reduced in the combustion process, it would be beneficial to create such reduction prior to injection of fuel into the engine. This study focused on PDE operation enhancements using dual detonation tube, concentric-counter-flow heat exchangers to elevate the fuel temperature up to supercritical temperatures. Variation of several operating parameters included fuel type (JP-8, JP-7, JP-10, RP-1, JP-900, and S-8), ignition delay, frequency, internal spiral length, and purge fraction. To quantify the performance, four key parameters examined were ignition time, deflagration to detonation transition time, detonation distance, and the percent of ignitions resulting in a detonation. In general, for all fuels except JP-10, increasing the fuel injection temperature decreased deflagration to detonation transition time and detonation distance, increased the percent of ignitions resulting in detonations (detonation percentage), and had no impact on ignition time. JP-10 was difficult to detonate, resulting in extremely poor performance. A minimum spiral length of 0.915 m (36 in) and a minimum purge fraction of 0.3 were determined. An increase in cycle frequency resulted in a decrease in deflagration to detonation transition time, but had little effect on ignition time and detonation distance. Analysis of ignition delay showed that 4 msec is the best ignition delay at high fuel injection temperatures, based on fire phase time and detonation percentage.
DTIC Accession Number
Helfrich, Timothy M., "Cycle Performance of a Pulse Detonation Engine with Supercritical Fuel Injection" (2006). Theses and Dissertations. 3560.