Direct Initiation Through Detonation Branching in a Pulsed Detonation Engine

Pulsed Detonation Engines are currently limited in operating frequency to the order of 40 Hz due to lengthy ignition and deflagration to detonation transition (DDT) times. An experimental study is conducted to determine the requirements necessary to eliminate these constraints through the concept of direct initiation. A branched detonation crossover setup is constructed and the operational requirements are determined. This research demonstrates the ability to directly initiate a detonation in a vacant tube from a detonation obtained through detonation branching. Using a hydrogen-air mixture, a tail-to-head detonation branching is achieved in which a detonation is seen to propagate from a spark ignited detonation tube, through a crossover tube and across a 1:2 diameter expansion ratio into a vacant second detonation tube. This effectively eliminates the ignition and DDT times associated with the conventional operation of the second tube. The closed-end pressure trace of a transferred detonation as deemed successful through wave speed measurements is analyzed and further solidifies the findings.