发动机供应系统中汽蚀管自激振荡特性试验

为研究汽蚀管在火箭发动机供应系统中的自激振荡特性，采用全尺寸的发动机泵后供应系统，并模拟供应系统在发动机中的边界条件，开展了汽蚀管动态液流试验。在不同的汽蚀管相对压力损失下，获得了不同位置处的压力振荡数据。试验结果表明，当汽蚀管处于汽蚀工作状态，汽蚀管下游脉动压力存在220~310 Hz范围的振荡，下游压力的自激振荡对汽蚀管上游系统无明显影响。随着汽蚀管相对压力损失的增大，汽蚀管下游的汽蚀振荡频率减小，汽蚀振荡幅值增大。在汽蚀管与主阀之间，振荡幅值沿流向逐步增大，从主阀至推力室头腔，振荡幅值逐步衰减。当汽蚀裕度过大时，汽蚀管下游出现大幅值的压力脉冲尖峰，并导致导管结构产生高幅值的脉冲形振动响应。

Experiment on Venturi Tube Self Oscillation in an Engine Feed System

In order to investigate the self-oscillation characteristics of the Venturi tube in the engine feed system, a dynamical flow experimental study of the Venturi tube is conducted, by using a full-scale engine feed system after pump, and the feed system boundary conditions in the engine are simulated. Under the different relative pressure losses of the Venturi tube, the pressure oscillation data at the different locations are obtained. The experiment results indicate that the pressure fluctuations after the Venturi tube have an evident oscillation frequency in the range of 220-310 Hz, when the Venturi tube is at the cavitation condition, while the pressure self-oscillation after the Venturi tube doesn’t have obvious influence on the flow system before it. Increase of the Venturi tube relative pressure loss can decrease the cavitation oscillation frequency and improve the cavitation oscillation amplitude. The oscillation amplitude increases along the flow direction from the Venturi tube to the main valve, while decreases from the main valve to the thrust chamber manifold. When the cavitation allowance of the Venturi tube is too severe, high-amplitude pressure pulses appear after the Venturi tube, making the pipe have response with high-amplitude vibration pulses.