Experimental study of the nozzle-ejector effect on the performance of a pulse detonation engine

In order to improve the propulsive performance of a Pulse Detonation Engine (PDE), several nozzle-ejector combinational configurations were designed and manufactured. A nozzle-ejector combinational configuration consisted of a nozzle and a straight ejector. There are three types of the nozzles in total, including straight nozzle(S nozzle), convergent nozzle(C nozzle)and convergent-divergent nozzle(C-D nozzle). The thrust of a gasoline-air PDE with three types of nozzle-ejector combinational configurations was measured experimentally. The nozzle-ejector configuration was installed positions X/D=-1,0,1 respectively(where X is the distance from detonation tube end to the head of ejector and D is the diameter of detonation tube.). The negative value represents the end of the detonation tube is fixed in the ejector. The thrust of every position and structure was conducted at 15Hz, 20Hz and 25Hz. The results indicated that the thrust augmentation of the PDE was dependent on the axial position of ejector, nozzle type and operating frequency. The thrust augmentation of the same nozzle-ejector combinational configuration changed with the operating frequency. Base on the present operating condition, the PDE with a straight nozzle-straight ejector combinational configuration had the best performance at the ejector position of X/D=0 at 15Hz.The highest thrust augmentation of the PDE with a convergent nozzle-ejector appears at position X/D=+1 at 20Hz. The PDE with a convergent-divergent nozzle-ejector got the best performance at the ejector position of X/D=-1 at 20Hz, and the thrust augmentation of 54.1% was the highest thrust augmentation of all these situations.