Effects of exit geometry on the performance of a pulse detonation engine

A preliminary analysis of a pulse detonation engine (PDE) driven ejector was performed. The thrust augmentation provided by a constant area cross-section ejector was computed. A range of partial-tube fill fractions and ejector diameters were simulated in this study. During the initial phase of this work, important issues associated with the imposed exit boundary conditions were addressed. Final analysis showed a rapid decrease in the PDE-ejector system performance as the ratio of the ejector to detonation tube diameter was increased. The thrust augmentation at the small ejector diameters was attributed to a compression wave that reflected off of the ejector wall and propagated back into the detonation tube. In addition, the sensitivity of the PDE-ejector system performance to the detonation tube fill fraction for all diameter ratios studied was seen to be similar to the case of the PDE without an ejector. Good agreement was observed between the simulations and available experimental data.