抽芯式斜流泵启动过程中转子动力学特性

针对抽芯式斜流泵异常振动现象,通过现场测试分析其振动诱因,进而基于能量守恒的拉格朗日方程建立机组转子非线性动力学模型,并通过与实测信号的峰峰值、振动频率等参数进行比较,验证仿真模型精度,重点研究泵组启动过程中轴心轨迹、振动频率等特征参数的动态响应,寻找降低水泵振动的技术措施.实测信号分析表明,抽芯式斜流泵异常振动诱因是机组启动伴生冲击力导致主轴发生偏移,当机组转速达到额定转速后,主轴偏移虽有所减小,却始终存在,造成机组产生不对中故障;仿真结果不仅证明了试验分析的准确性,同时也揭示了伴生冲击力与机组振动的内在联系:较强的冲击力会加剧转子不对中现象,形成剧烈机组振动,反之则相反.改善机组开机方式是降低伴生冲击力、减弱机组振动和提高机组运行可靠性的有力措施.

Rotor dynamic feature of core pulling mixed flow pump during startup process

Focusing on the abnormal vibration of a core pulling mixed flow pump, the vibration causes were explored by the tested signal analysis, and then the rotodynamic model was established based on the Lagrange equations, which complies with the energy conservation. Comparing the peak-peak va-lue and vibration frequency of tested signals with that of simulated signals, the simulation precision was verified, and the start-up characteristics, such as the shaft orbit and vibration frequency, were simulated to search the vibration mitigation measures. The test signal analysis shows that, the impact force at the start-up process causes the rotor misalignment, and the misalignment will reduce but not disappear when the pump′s rotational speed reaches the design value. The simulation results verify the precision of test analysis, and the internal connection between the accompanied impact force and units vibrations was studied. The powerful impact force is more likely to induce the severe vibration and misalignment. Because the accompanying impact force is induced by motor direct start, to improve unit start-up mode and reduce the impact force can weaken vibration and enhance the operation reliability effectively.