Abstract: In order to investigate the propagation characteristics of back-pressure waves in multi-tube pulse detonation engine，a series of experiments and numerical simulations were carried out. The propagation characteristics of back-pressure waves of four-tube pulse detonation combustors were measured when the combustors operated at two firing patterns: all tubes firing simultaneously and all tubes firing sequentially. Numerical simulations were carried out to investigate the flow characteristics in the air buffer chamber. The length of the air buffer chamber was varied and a splitter was installed in the air buffer chamber numerically to study their effects on the propagation of back-pressure waves. The experimental results show that a strong back-pressure wave was observed in the air buffer chamber when all tubes were fired simultaneously and the peak value was about 0.12MPa. However，when all tubes were fired sequentially，the air buffer chamber experienced four times pressure oscillation in a single cycle and the amplitude was smaller than that when all tubes were fired simultaneously. The numerical results indicate that there was a reverse flow in the engine inlet when the back-pressure wave propagated into the air inlet. The velocity of reverse flow was smaller when the tubes were operated at sequential firing pattern. The amplitude of the back-pressure waves was reduced when the length of air buffer chamber increased. The velocity of reverse flow was also reduced. No reduction of amplitude of the back-pressure waves was observed when the splitter was installed in the air buffer chamber.

Key words: Multi-tube pulse detonation combustor；Back-pressure wave；Experiment；Numerical simulation；Reverse flow；Air buffer chamber

摘要： 为了研究多管脉冲爆震发动机的压力反传特性，采用数值模拟和试验相结合的方法对四管爆震室的压力反传特性进行研究，测量了四管爆震室同时点火和分时点火这两种工作模式下的压力反传规律，利用数值模拟对四管爆震室共用进气道进行研究，分析了共用进气道长度以及在共用进气道内加装分流板对压力反传的影响。试验结果表明，四管爆震室同时工作时，共用进气道产生一道很强的压力扰动波，其峰值压力接近0.12MPa；四管爆震室分时工作时，共用进气道在一个循环内出现四次压力扰动，但扰动波的峰值压力较小。数值模拟的结果表明，在两种工作模式下，爆震室产生的反传压力使发动机入口产生高速倒流，四管分时工作时倒流的速度较小。随着共用进气道的长度增大，反传压力的峰值降低，但发动机入口处仍然存在倒流现象，倒流的速度随着共用进气道的长度增大而减小。共用进气道内加装分流板对反传压力的峰值并没有削弱作用。

关键词: 多管脉冲爆震燃烧室；压力反传；试验；数值模拟；倒流；共用进气道