One-dimensional unsteady design method for pulsed detonation engine nozzles

Abstract

A new design method for pulse detonation engines nozzle was developed theoretically. The effects of non-uniform exhaust on the performance of pulse detonation engine were analyzed by constant volume cycle model. The results showed thrust losses induced by the non-uniform exhaust could be decreased by increasing fill pressure ratio. If the fill pressure ratio was larger than 10, the performance losses with a fixed optimal nozzle could be controlled within 3%. The optimal area ratio of the nozzle was obtained when the time-averaged pressure at the nozzle exit equals the ambient pressure. This was also applicable to one-dimensional unsteady frictionless pulse detonation engine model. Thus an optimal area of the nozzle could be calculated by the time-averaged total pressure. Compared with the zero-dimensional results obtained by numerical search technique, the errors of predicted optimal area could be neglected if fill pressure ratio is too large to prevent shock from propagating back to the nozzle. And the errors of predicted optimal area are lower than 5% compared with the results of the one-dimensional unsteady pulse detonation engine model.