静环振动对涡轮泵端面密封失效的影响

Effects of Stationary Seal Ring Vibration on End-FaceSealing Failure in Turbo Pump

关键词:  端面密封  数值模拟  压力脉动  振动  涡轮泵

Key words:  End-face seal  Numerical simulation  Pressure fluctuation  Vibration  Turbo pump

摘要:

为了深入认识涡轮泵端面密封的失效机理，采用动网格方法和可压缩液体模型模拟了静环简谐振动对密封腔内流体的激励作用，获得了静环脱开的力学条件，并研究了静环振动对密封失效的影响规律和改进措施。计算结果表明，静环简谐振动将激励密封腔内流体产生压力脉动，并在静环两侧形成较大的压力差；静环承受的净作用力周期性波动，在位移处于π/2相位时达到最大值；随着静环振动频率和幅值增大，最大净作用力也不断增大，最终达到静环脱开泄漏的条件。在简谐振动作用下，净作用力峰值受振动频率影响较大；在脉冲冲击作用下，净作用力峰值与冲击过程有关，而与脉冲的出现频率关系不大。通过连通静环两侧的流体，可以减弱静环振动产生的激励作用，大幅降低净作用力的脉动峰值，从而提高端面密封的可靠性。

Abstract:

In order to understand the failure mechanism of turbo pump end-face seal，the dynamic grid method and the compressible liquid model were used to simulate the excitation effect of stationary seal ring vibration on the fluid in the seal cavity，and the mechanical conditions of the seal ring undoes are obtained. The influence rules and improvement measures of the stationary seal ring vibration on the sealing failure were also studied. The results show that the ring harmonic vibration will motivate fluid pressure pulsations in the seal cavity，and lead a larger pressure difference on both sides of the ring. Net force in the stationary seal ring changes periodically which will reach the maximum value on the displacement of π/2 phase. With the vibration frequency and amplitude increasing，the maximum net force also increased，ultimately the stationary seal ring will undo and leak. Under the effect of simple harmonic vibration，the peak value of net force is greatly influenced by the vibration frequency. Under the impulse shock process，the net force is related to the impact process，but is not much related to the frequency of the pulse. By connecting the fluid on both sides of the ring，the exciting effect generated by the vibration is weakened，and the peak value of the net force is greatly reduced，so the reliability of the end-face seal is improved.