Single detonation backpressure suppression tests on different isolators in a valveless airbreathing pulse detonation engine

To better suppress the backpressure generated by detonation from propagating upstream in a valveless airbreathing detonation engine, a flow path consists of a novel isolator and a detonation tube with a length of 750 mm, along with a comparison group of four different geometries, were fabricated. Experimental study was carried out to investigate the parameters, including backpressure peak and back-propagation velocity, by means of series single detonation tests, utilizing ethylene as fuel and oxygen-enriched air as oxidizer. The results indicate that the backpressure peak can be effectively reduced by more than 40% through introducing a divergent path for the backflow, and the isolator with a larger volume of divergent room will result in a lower backpressure peak. As for the thorn-shaped geometry, it is able to reduce the backpressure peak during the early stage of the backpressure propagation and decelerate the propagation velocity of backpressure, apparently.