| Summary: | Rapid and efficient initiation of hydrocarbon/air mixtures has been identified as one of the critical and enabling technologies for Pulse Detonation Engines (PDEs). Although the NPS Rocket Propulsion Laboratory has successfully demonstrated fuel/air detonations in a valveless pulse detonation engine using ethylene, propane, and JP-10 fuels, past engine designs have relied upon a sensitive fuel/oxygen initiator unit. To realize the increased thermodynamic efficiencies of PDEs and thus compete with ramjets and other supersonic platforms, it is imperative to eliminate any need for supplementary oxygen in an air-breathing PDE design. This thesis examined ignition technologies and initiator designs which did not require auxiliary oxygen, including capacitive discharge systems and the developing technology of Transient Plasma Ignition (TPI). The current NPS pulse detonation engine architecture was modified to evaluate the various ignition strategies in a PDE operating on an ethylene/air mixture at simulated supersonic cruising conditions. Comparisons were based upon ignition success rate, ignition delay time, detonation wave speed, and Deflagration-to-Detonation (DDT) distance. Reliability and performance of the TPI system proved to be superior to conventional ignition systems. Furthermore, successful initiation of a PDE operating at a frequency of up to 40 hertz was demonstrated without the use of supplementary oxygen.
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