Fast pulser for high-altitude ignition research

A jet engine can flame out at high altitude because the igniter cannot couple enough energy into the low-pressure air-fuel mixture. To reignite the engine, the aircraft must descend to a lower altitude where the air pressure is higher. Under a recent U.S. Air Force SBIR grant, Diversified Technologies, Inc. designed and built a fast ignition pulser. The pulser was delivered to the Air Force Research Laboratory for testing to determine the optimum parameters for high-altitude jet ignition. The pulser, based on magnetic pulse compression, is immune to arcs at the output. It delivers a pulse at 27 kV and 37 mJ with a rise-time of 17 ns at a pulse rate of 8 kHz. The overall efficiency is 38%. This paper discusses the design and performance of the laboratory pulser.