A study of detonation initiation by shock reflection for pulse detonation engines

This project will report on the investigation of a new technique to initiate detonation via the interaction of a high-speed flame/shock complex and an obstacle. A series of experiments were performed where a flame was ignited at the closed end of a tube partially filled with orifice plates leading up to a "reflecting" obstacle. The obstacles tested in this study were: a circular front plate followed by a back-up orifice plate ring, a central cone followed by a back-up orifice plate, and a reflecting orifice plate.; Tests were performed in a 3.05 m long detonation tube with an internal diameter of 0.1397 m. The first 1.36 meters of the tube was filled with orifice plates spaced at roughly one tube diameter with a 0.102 m opening. The combustible mixture investigated was stoichiometric ethylene-oxygen diluted with nitrogen. Mixture reactivity was varied by changing the amount of nitrogen dilution. The most effective obstacle is the one that can initiate a detonation wave in the least reactive mixture, i.e. the highest nitrogen dilution. (Abstract shortened by UMI.)...