Investigation of Transient Plasma Ignition

41st AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit, 10 - 13 July 2005, Tucson, ArizonaReduction of auxiliary oxygen amounts currently used in Pulse Detonation Engines (PDEs) is necessary to compete with existing Ramjet technologies. This paper investigates a Transient Plasma Ignition (TPI) system and finds that this technology enables the complete removal of any auxiliary oxygen requirements of current PDE systems. TPI was tested and compared with a traditional capacitive discharge spark ignition system within ethylene/air mixtures under dynamic fill conditions. Successful operation was achieved at up-to 40Hz repetition rates. Ignition delay times, Deflagration-to-Detonation transition (DDT) distances and DDT times, detonation wave speeds, and detonation initiation success rates were measured and analyzed for various mass flow rates, for various ethylene-air mixtures, and for various lengths of turbulence generating Schelkhin spirals. A transient plasma dual- electrode concept was also investigated and analyzed. Results show that TPI system is more effective than conventional spark ignition systems. The TPI system shows near 20% improvements to DDT distances and up-to 2.5 reduction factor in DDT times. In addition, at high flow rates, where the flames normally extinguish when employing the spark ignition system, the TPI system was able to ignite mixtures and effectively initiate detonation waves. Detonation initiation success rates greater than 94% were obtained at cycle frequencies of up-to 40Hz. Further work is required to discern the TPI system sensitiv i ty to back pressures; additional instrumentation is requi red to determine axial variations in equivalence ratio