流量调节器管路系统自激振荡特性研究

Auto Oscillation of Flow Regulator Pipe System

关键词:  液体火箭发动机  流量调节器  管路系统  瞬态过程  自激振荡  频率特性

Key words:  Liquid rocket engine  Flow regulator  Pipe system  Transient process  Auto oscillation  Frequency characteristics

摘要:

流量调节器管路系统在小流量大压降工况下会出现低频自激振荡现象。为了深入认识自激振荡产生机理，结合某稳流型流量调节器及管路系统，基于流量调节器弹簧振子动力学模型开展数值仿真研究。数值仿真得出自激振荡频率为94Hz，与发动机试验结果一致。分析了流量调节器结构参数对系统稳定性的影响作用，三角形滑阀节流口能够抑制管路系统自激振荡。自激振荡产生机理是液动力随滑阀节流口型面振荡，并对管路系统形成正反馈作用，当流量调节器综合刚度系数<0时，管路系统就失稳产生振荡。某流量调节器的负载特性试验表明，随着流量调节器压降升高，管路系统稳定性变差。仿真获得的幅频特性，稳定边界与试验结果一致。

Abstract:

Low-frequency auto oscillation occurs in the pipeline system of flow regulator under the condition of small flow and large pressure drop. In order to deeply understand the mechanism of auto oscillation， a numerical simulation study was carried out based on the dynamic model of spring oscillator of flow regulator in combination with a certain output-flow-stabilized regulator and pipeline system. The numerical simulation results show that the auto oscillation frequency is 94 Hz， which is consistent with the engine test results. The influence of flow regulator structure parameters on the stability of the system was analyzed. The triangular slide valve throttle can suppress the auto oscillation of the pipeline system. The mechanism of auto oscillation is hydrodynamic oscillation with the throttling interface of the slide valve， and it forms a positive feedback effect on the pipeline system. When the comprehensive stiffness coefficient of the flow regulator is less than zero， the pipeline system will be unstable and oscillate. The load characteristic test of a certain flow regulator shows that the stability of pipeline system becomes worse as the pressure drop of flow regulator increases. The amplitude-frequency characteristic and stability boundary obtained by simulation are consistent with the test results.