Pulse Detonation Cycle at Kilohertz Frequency

To realize kilohertz and higher frequency of a pulse detonation cycle (PDC), enhancement of deflagration-to-detonation transition (DDT) is necessary. A novel semi-valveless PDC method, in which the inner diameter of the oxidizer feed line is equal to that of the combustor, can increase the pressure of detonable mixture by increasing total pressure of supplying oxidizer. In demonstration experiments, ethylene as fuel, pure oxygen as the oxidizer and the combustor having an inner diameter of 10 mm and length of 100 or 60 mm were used. A PDC was successfully operated at the frequency of up to 1916 Hz. Under the condition of 1010 Hz operation, the total pressure of supplying oxidizer were varied. As the results, it was found that the DDT distance and time decreased by approximately 50% when the total pressure of supplying oxidizer increased by 242%.