火箭发动机泵后供应系统水力激振试验

Hydraulic vibration experiment on a rocket engine feed system after pump

为了研究某型发动机泵后供应系统的动力学特性,对全尺寸的氧泵后供应系统在中、高频范围内开展了水力激振试验。试验数据表明:供应系统的谐振特性被激发起来。在试验条件下,可以清晰地辨识出泵后供应系统的前4阶谐振频率和振型。第1阶谐振频率响应幅值最高,第2阶和第3阶相当,响应幅值次之,第4阶响应幅值再次之。在外界扰动下,该发动机泵后供应系统能够较容易地达到流体谐振状态,当外界扰动频率接近其谐振频率时,供应系统沿程脉动压力出现了明显的共振波形。在不同的谐振频率下,喷前腔位置均为压力振荡的波节位置,也即为流量振荡的波腹位置。

The dynamical characteristics of liquid rocket engine propellant feed system after pump have important effect on the stability of thrust chamber.In order to investigate the dynamical characteristics of the propellant feed system after pump in an engine,the hydraulic vibration experiments within the medium and high frequency ranges of the full scale engine feed system after oxidizer pump were conducted.Test data indicate that resonance characteristics of the engine feed system were excited.Under the test condition,the first four resonant frequencies and the vibration modes can be clearly revealed.The first resonant frequency had highest response amplitude,while the second resonant response amplitude was lower than the first one,and similar to the third one.The fourth resonant response amplitude was further lower than the third one.Under the external pressure fluctuation,this engine feed system after pump can easily achieve the resonant condition.When the fluctuation frequency was close to the resonant frequencies of the feed system,the pressure oscillations along the feed system presented obvious resonant wave shapes.The position of the injector manifold is always the wave node of pressure oscillation,namely the wave anti-node of flow oscillation,under different resonant frequencies.