Study on operation and propulsion features of a pulse detonation rocket engine with secondary oxidizer injection

To explore an effective method which can help to reduce the pressure and velocity fluctuations and promote the utilization of kinetic energy in the exhaust products of a pulse detonation chamber, a secondary oxidizer injection method has been proposed and investigated experimentally. A gasoline based valveless pulse detonation system was employed and it operated stably from 10 to 50 Hz. With the extra injection, pressure and velocity fluctuations of the detonation products were reduced dramatically, and a thrust increment up to 29.5% was achieved on the same account of fuel. It provides a new way to promote the propulsion performance of pulse detonation engines beyond the traditional methods, e. g. nozzle and ejector optimization. Moreover, it can be used as a supplement to nozzles, by the combination of a fluidic nozzle, a maximum thrust increase of 75.9% was obtained in this study. The reduction of pressure and velocity fluctuations is believed to provide most of the benefits on thrust improve, and stratified fuel distribution, after-burning, and partial-fill effects are also main reasons especially in higher frequencies.