Experimental investigation of the effect of bell-shaped nozzles on the two-phase pulse detonation rocket engine performance

The performance of a pulse detonation rocket engine (PDRE) with converging- diverging nozzles of different configurations is studied. Liquid kerosene and gaseous oxygen are used here as a fuel and an oxidizer, respectively. Nitrogen is used as a purge gas. The operating cycle frequency varies from 10 to 40 Hz. The fill-fraction is changed by changing the PDRE length. The experiments are performed under the condition that the reactant filling pressure and the back pressure are both 1 atm. All nozzles tested improve the PDRE performance in the case with the fill-fraction of 0.73 and the cycle frequency of 40 Hz. The nozzle with the contraction area ratio of 5.325 and the expansion area ratio of 12 ensures the maximum thrust augmentation, which is approximately 21%. The tested nozzles with the contraction area ratio equal to 5.325 are found to be detrimental to the PDRE performance at the fill-fraction of 0.29 and beneficial at the fill-fraction of 0.37.