Development of a compact liquid fueled pulsed detonation engine with predetonator

A compact PDE platform has been constructed, which features a pre-detonator with 1 in. i.d. followed by a 30° smooth area change nozzle that expands to a 4 in. i.d. main combustor. The pre-detonator is equipped with a Shchelkin spiral and runs on propane-oxygen mixtures ignited by means of a low energy automotive ignition system. Pre-heated liquid fuel is sprayed into a current of pre-heated air and thoroughly mixed in specially hand built mixing chambers, before being supplied into the main combustor. The design includes four such mixing chambers. All gas and fuel supplies are performed using fast acting solenoid valves, which are controlled using signals from a computer based data acquisition system. The multiple valve injection and short size of the PDE enable it to be operated at cycle frequencies as high as 100 Hz. The PDE set up is water cooled allowing long duration testing. Diagnostics are performed using dynamic pressure transducers and photo-diode based optical transducers. A variety of liquid fuels, including Jet A and kerosene are expected to be tested in the near future. Thus a platform is now available for performing structured detonation studies. The different aspects of the PDE system design are detailed in this paper.