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

摘要： 为了研究燃烧室长度对液态燃料旋转爆轰发动机性能的影响，在环形阵列式连续旋转爆轰发动机上，以汽油/富氧空气为工质，详细分析了不同燃烧室长度下爆轰波传播模态、平均压力峰值和传播速度的变化特征。测量了发动机模型在不同燃烧室长度下的一维推力，分析了推力和燃料比冲的变化趋势。实验结果表明:出口背压为大气压时，空气流量为762.9g/s，氧气流量为182.4g/s，汽油流量为84.3g/s，当量比为0.82，燃烧室长度L=235mm工况下爆轰波为稳态双波对撞模态，平均压力峰值和传播速度分别为0.9MPa和1068m/s，爆轰波传播频率为2.223kHz。当L＜235mm时爆轰波为非稳态双波对撞模态，平均压力峰值变化较小，传播速度随着燃烧室长度变短而降低。仅在L=135mm工况下，爆轰波传播速度略高于L=155mm工况点，推力和燃料比冲分别为579.5N和701.5s。当155mm≤L＜235mm时推力和燃料比冲随燃烧室长度增加而缓慢增大，L=235mm时推力和燃料比冲分别为607.3N和735.1s，L＞235mm时推力和燃料比冲变化趋于平缓。

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