四瓦可倾瓦轴承瓦块摆动特性

Swing Characteristic of Pads in Four-pad Tilting Pad Bearing

以第四代核电机组高温气冷堆氦风机导轴承为对象,系统研究四瓦可倾瓦轴承的瓦块摆动特性。理论推导得出量纲一瓦块摆角取决于轴承结构参数、预负荷和偏心率,但是与轴承间隙比、轴颈转速和润滑油黏度无关。数值分析表明:瓦块摆角特性由瓦块与载荷周向相对位置、预负荷和偏心率决定。轴承结构参数确定时,与载荷正对瓦块的摆角曲线的形状取决于预负荷,预负荷小于0.5时其摆角随偏心率增大先增加后减小,预负荷大于0.5时摆角则随偏心率的增大而逐渐减小;与载荷侧对瓦块的摆角在预负荷较小时随偏心率增大一直增大或减小,预负荷较大时则随偏心率的增大先保持不变然后减小。瓦块摆角对最小油膜厚度影响很大,瓦块摆角可能为负值,从而使最小油膜厚度较固定瓦时的最小油膜厚度偏大。研究结果为氦风机安全运行分析提供了依据。

The swing characteristic of pads on four-pad tilting pad bearing is studied systematically with the guide bearing for helim circulator in fourth generation nuclear power units HTR as object.Theoretical derivation reveals that dimensionless pad pendulum angle depends on structural parameters,preload and eccentricity,but independent of viscosity of lubrication oil film,shaft rotating speed and clearance.Numerical analysis shows that：pad pendulum angle is determined by pad circumferential position relative to the load,preload and eccentricity.When the structural parameters of tilting pad bearing are constant,pendulum angle curve of pad facing the load was depend on preload,its pendulum angle increases first and then decreases with the eccentricity ratio increase while the preload less than 0.5,when the preload is greater than 0.5 its pendulum angle decreases gradually with the eccentricity ratio increase; pendulum angle curve of pad side of the load increases or decreases with the eccentricity ratio increase when the preload is smaller,and remains constant first and then decreases with the eccentricity ratio increase when the preload is greater.Pad pendulum angle has great influence on minimum oil film thickness; its value maybe negative thus leads to the minimum oil film thickness greater than fixed pad.The study results provides basis for safety operation analysis of the helim circulator.