To analyze the startup and operation stability problems of high pressure multistage centrifugal pump water lubricated bearing - rotor system, analysis and judgment about the dynamic stability of water lubricated bearing-rotor system were performed on the aspects of critical speed, bearing dimensionless film composite stiffness, stability margin of logarithmic decay rate and the sudden unbalance response of excitation system. Physical and mathematical model were established to study the dynamic characteristics of the pump bearing-rotor system. The calculated first critical speed of the bearing - rotor system under rigid support and the modular elastic support was consistent with the stability condition. The values of dimensionless film integrated bearing stiffness, such as keq and yst were below zero, and the logarithmic decay rate of the first four modal analysis characteristic values at a rotational speed of 3000 r/min was greater than zero, which also demonstrate that the system was stable. This water lubricated bearing - rotor system was certified to be a stable system by responsive spectrum analysis on constant speed (500, 2 500, 5 000 and 10 000 r/min) , working speed (2950 r/min), and different starting acceleration suddenly adding exciting force. Therefore, this water lubricated bearing rotor system of high pressure multistage pump is a stable rigid system.%针对某高压多级离心泵水润滑轴承-转子系统的启动、运行稳定性问题,分别从临界转速、轴承无量纲液膜综合刚度、对数衰减率稳定性裕度、突加激励下系统不平衡响应等稳定性判据对该泵的水润滑轴承-转子系统的动力稳定性进行分析及判定.在建立物理模型与数学模型的基础上,计算得到的刚性支承轴承-转子系统与模化后的弹性支承轴承-转子系统的第一临界转速值都符合转子稳定性条件；轴承无量纲液膜综合刚度keq、Yst均小于零；3 000 r/min下前四阶模态分析特征值的对数衰减率均大于零,分别满足其稳定性判据；对于恒定转速(500、2 500、5 000和10 000 r/min)下突加激励的轴承节点响应频谱、工作转速(2 950 r/min)下各节点激励力响应值、不同启动加速度下各节点响应图谱等的分析也表明该转子是稳定的；因此,该高压多级离心泵的水润滑轴承-转子系统是一个稳定的刚性系统.
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