非接触动静结合型机械密封的主动可控性及其脱开机理

针对非接触动静结合型机械密封运行中的脱开现象和泄漏量控制要求,研究基于改变闭合力的机械密封主动可控方法.在原有基础上完善了动静结合型机械密封主动可控的原理,包括控制策略、控制元件及控制流程;结合高速涡轮泵轴端机械密封,给出了主动控制的设计过程,并理论和试验研究了其可控性和受可控元件影响的性能规律.完善了现有的机械密封脱开理论,并结合试验结果对可控型机械密封的脱开转速进行了机理分析.研究结果表明:提出的基于闭合力调控的密封可控性策略及控制敏感性参数范围[1,3.19],可满足对涡轮泵轴端机械密封泄漏量的动态主动控制;完善的脱开转速理论能合理地解释机械密封起飞阶段的端面非接触状态向接触状态转变过程.研究结果对于特殊工况下特种机械密封的设计、运行监测及动态控制具有参考价值.

Active controllability and separation mechanics of non-contact hydrostatic mechanical seal

To explain the separation phenomena and meet the requirement of the leakage of the non-contact hydrostatic mechanical seal, an active controllable method for mechanical seals based on the change of the closing force was proposed. The principle of the method was developed, including: control strategy, control components and control flow. Taking the shaft mechanical seals in the high-speed turbopump as the object, the design for the controllable seal was carried out, and the influence of the controllability and the control elements on the performance of the seals were obtained by the theoretical and experimental methods. The existing separation speed theory was developed, and with the experiment results, the mechanism of the separation speed for the controllable seal was validated. The results show that the strategy of regulating the closing force could satisfy the leakage of the seal; and the range of the control sensitivity coefficient is[1, 3.19]. The developed separation speed theory can reasonably explain the transformation process from the contact state to non-contact state between the mechanical seal faces in the takeoff stage. The results are helpful to design, monitor and control the special mechanical seal under special working conditions.