EFFECTS OF CORONA, SPARK AND SURFACE DISCHARGES ON IGNITION DELAY AND DEFLAGRATION-TO-DETONATION TIMES IN PULSED DETONATION ENGINES (POSTPRINT)

Abstract : The purpose of the research described herein is to compare the ignition delays in an experimental pulsed detonation engine produced by thermal and non-thermal ignitions. The commercial thermal ignition has a pulse duration of about 1 microsec, whereas the non-thermal ignitions have pulse durations of 100 nanosec. Ignition delay is an important factor, along with fill and purge times, that limit the maximum repetition rate and thrust of pulsed detonation engines. For stoichiometric fuel-air mixtures with aviation gasoline at 1 atmosphere and 360 - 480 K, an ignition delay of 6 millisec was observed with a non-thermal ignition, whereas the ignition delay was 11 millisec with an aftermarket automotive ignition. By replacing the resistive cable and resistor of the aftermarket ignition with a non-resistive cable and surface discharge igniter, its ignition delay was reduced to 7 millisec, which is comparable to that produced by the non-thermal ignitions.