核电常规岛给水泵CAP1400转子动力学分析

Dynamic Analysis of the CAP 1400 Rotor of a Feedwater Pump in the Conventional Island of a Nuclear Power Station

针对常规岛给水泵CAP1400可倾瓦滑动轴承-转子系统安全、平稳运行问题,利用有限元QZ算法计算不同支撑工况下的临界转速。首先设计五瓦可倾瓦轴承,计算了轴承的油膜厚度、刚度和阻尼等非线性动力参数;其次,建立轴承-转子系统模型,采用油膜的特性数据求解可倾瓦轴承-转子系统在刚性支撑、弹性支撑以及"湿态"支撑工况下的临界转速;最后,对给水泵进行联机试验,采集不同流量工况下轴承不同方位的振动值。结果表明:可倾瓦轴承的油膜厚度在0.04-0.05 mm之间,刚度随着转速的增大而增大,而阻尼反之;刚性支撑下的临界转速大于弹性支撑,而"湿态"工况下水膜刚度的增加使得一阶临界转速在8 100-8 777 r/min之间,远大于实际运行速度;试验测得轴承垂直、水平和轴向上振动值与振动速度均满足国家标准。临界转速的计算与试验结果为CAP1400常规岛给水泵可倾瓦轴承-转子系统安全平稳地运行提供了设计依据。

In the light of the problems relating to the safety and smooth operation of the CAP1400 tilting-pad sliding bearingrotor system of a feedwater pump in the conventional island in a nuclear power station,by using the finite element QZ algorithm,calculated was the critical rotating speed under various supporting conditions. Firstly,a tilting-pad bearing with five pads were designed and such non-linear dynamic parameters of the bearing as the oil film thickness,stiffness and damping etc. were calculated. Secondly,a model for bearing-rotor systems was established and the solutions to the critical rotating speed of the tilting-pad bearing-rotor system under the rigid supporting,elastic supporting and 'wet-state'supporting conditions were sought by using the characteristic data of the oil film. Finally,an on-line test was performed of the feedwater pump and the vibration values in various directions and at different locations at various flow rates were acquired. It has been found that when the oil film thickness of the tilting-pad bearing is between 0. 04 mm and 0. 05 mm its stiffness will increase with an increase of the rotating speed and the damping will be in this contrary. The critical rotating speed under a rigid supporting will be higher than that under the elastic supporting while an increase of the stiffness of the water film under the 'wet-state'condition will make the first-order critical rotating speed be in a range from 8 100 r /min to 8 777 r /min,far higher than the actual operation rotating speed. All the vibration values and the vibration speeds of the bearing measured during the test in the vertical,horizontal and axial direction meet the national standards. The calculation result of the critical rotating speed and the test one can offer a design basis for safe and smooth operation of the tilting-pad bearing-rotor system of CAP 1400 conventional island feedwater pumps.