有阀式脉动喷气发动机出口瞬态速度场测量

Measurement of transient velocity field at exit zone of valve pulse jet engine

通过使用TR-PIV(time-resolved-patricle image velocimetry)系统对某亥姆霍兹型有阀式脉动喷气发动机出口瞬态速度场进行测量.实验结果表明:有阀式脉动喷气发动机出口压力及速度场呈明显的周期性变化过程,时均速度最高的区域并不在尾喷管出口截面,排气阶段的旋度及持续时间均大于吸气阶段.有阀式脉动喷气发动机出口未完全膨胀的高温燃气在排出尾喷管后仍会继续膨胀,对于提高性能不利.

Advanced TR PIV （time-resolved-particle image velocimetry） system was used to measure transient velocity field at a Helmholtz-type valve pulse jet engine exit zone. Test results indicate the cyclical evolution process of velocity field and pressure at the exit zone of valve pulse jet engine, and the maximum time averaged velocity of the engine is not at the nozzle＇s exit. The vorticity and duration in the exhaust stage was stronger than that in the inspiratory stage. Measured velocity field shows that transient high-temperature combustion gas does not fully expand at the exit plane, but continues to be expanded at the following exit zone, which is disadvantageous for improving the performance of pulse jet engine.