关键词: 连续旋转爆轰发动机；液态燃料；双波对撞模态；燃烧室长度；推力；比冲

Abstract: To study the effects of combustor length on liquid-fueled rotating detonation engine performance， the detonation propagation modes， average peak pressures and detonation propagation velocity were systematically analyzed in a ring-shaped arrangement continuous rotating detonation engine when the combustion chamber length varied. The mixtures used in the present study were gasoline and oxygen-enriched air. The one dimensional thrust of the engine model was also measured， and the tendencies of thrust and fuel specific impulse were analyzed. The experimental results show that， when the backpressure was one atmosphere， the mass flow rate of air， oxygen and gasoline were 762.9g/s， 182.4g/s and 84.3g/s (which equaled 0.82 equivalent ratio)， and the combustor length L was 235mm， the detonation maintained steady bifurcation mode， the average peak pressure and propagation velocity were 0.9MPa and 1068m/s， and the detonation propagation frequency was 2.223kHz. When the length was less than 235mm， the detonation propagation was unsteady bifurcation mode， while the average peak pressure changed slightly. The propagation velocity was reduced as combustor length shortened. However， when the combustor length was 135mm， propagation velocity was slightly higher compared to that of 155 mm， the thrust and fuel specific impulse were 579.5N and 701.5s. When the combustor length was between 155mm and 235 mm， the thrust and fuel specific impulse increased slowly with the increase of the combustor length. The thrust and fuel specific impulse were 607.3N and 735.1s under the length of 235mm. With further increase of the combustor length， the variations of thrust and fuel specific impulse were slighter.

Key words: Continuous rotating detonation engine；Liquid fuel；Bifurcation mode；Combustor length；Thrust；Specific impulse