大型立式水泵机组电机滑动推力轴承润滑与承载特性研究

发布时间：2018-09-05 17:10

【摘要】：大型立式水泵机组电机推力轴承,起着承受水泵机组转动部件轴向力的作用,是保证水泵机组可靠稳定运行的重要部件,也是泵机组运行寿命、大修周期和可靠性的主要控制性因素。研究动压推力轴承的润滑性能和承载能力,可以为改进推力轴承设计、提高可靠性提供依据。本文针对大型立式轴流泵机组电机动压滑动推力轴承,运用CAD软件建立推力轴承流体域三维模型,运用Gambit软件进行网格划分并设置压力边界条件,后导入到Fluent软件,计算润滑流场与压力分布；分析推力轴承承载力的影响因素,揭示规律；研究推力轴承实际运行过程的问题。研究取得如下成果：(1)镜板旋转带动润滑油运动,产生动压,在推力瓦表面形成高压区域,从最大压力中心到瓦面四周,压力逐渐减小。(2)立式水泵机组正常运行时,算例电机推力轴承瓦面平均油膜厚度为0.0675mm,弹性金属塑料轴瓦变形量一般为2×10-4～9×10-4mm,仅为油膜厚度的0.3%-1.3%,变形量微乎其微,计算时可以不考虑。(3)油膜厚度对推力瓦承载力影响很明显,油膜厚度越小,承载力越大,特别是油膜厚度较小的情况下,油膜厚度很小的变化也会造成承载力较大的改变。(4)相同支撑点油膜厚度下,抗重螺栓偏心距越大,瓦面倾角增大,高压中心越偏向于出油口方向。转速越大,承载力越大。(5)推力瓦面安装高度误差,影响瓦块之间载荷均匀分布；一块瓦高于其他瓦0.01～0.02mm时,其载荷较平均值增大36%～75%。(6)立式泵机组起停过程中,低速运转时,推力轴承承受所有转动部件自重和小部分轴向水推力,此时瓦面油膜厚度很小,润滑性能差,摩擦阻力大,对轴承工作面损害大,机组起停不宜过频,起停时间不宜长。(7)润滑油粘度影响推力轴承承载力,粘度越大承载力越大,推力轴承荷载一定时,润滑油粘度越大,瓦面油膜厚度越大,润滑性能越好。
[Abstract]:The motor thrust bearing of large vertical water pump unit plays an important role in bearing the axial force of the rotating part of the pump unit, and is an important component to ensure the reliable and stable operation of the pump unit, and also the operating life of the pump unit. Major controlling factors for overhaul cycle and reliability. The study of lubricating performance and bearing capacity of dynamic thrust bearing can provide basis for improving the design and reliability of thrust bearing. In this paper, a three-dimensional model of thrust bearing fluid domain is established by using CAD software for electrically driven sliding thrust bearing of large vertical axial flow pump unit. Gambit software is used to mesh the thrust bearing and set up pressure boundary conditions, and then it is imported into Fluent software. The lubrication flow field and pressure distribution are calculated, the factors affecting the bearing capacity of thrust bearings are analyzed, and the rules are revealed. The problems in the actual operation process of thrust bearings are studied. The results are as follows: (1) the rotating mirror plate drives the lubricating oil movement to generate dynamic pressure, forming a high pressure area on the surface of the thrust pad, and the pressure decreases gradually from the maximum pressure center to the surrounding of the tile. (2) when the vertical pump unit is in normal operation, The average oil film thickness of motor thrust bearing bush is 0.0675 mm, and the deformation of elastic metal plastic bearing is generally 2 脳 10 ~ (-4) ~ 9 脳 10 ~ (-4) mm, which is only 0.3- 1.3mm of oil film thickness, and the deformation is very small. (3) the effect of oil film thickness on the bearing capacity of thrust bush is very obvious. The smaller the oil film thickness, the greater the bearing capacity, especially when the oil film thickness is small, the smaller the oil film thickness, the larger the bearing capacity will be. (4) under the same supporting point oil film thickness, the greater the eccentric distance of the anti-weight bolt, the bigger the tile face inclination. The higher the high pressure center is, the more inclined it is to the outlet. The higher the rotational speed, the greater the bearing capacity. (5) the error of installation height of thrust pad affects the uniform distribution of load between tiles, and when one tile is higher than other tiles 0.01~0.02mm, the load increases by 3675% than the average. (6) during the starting and stopping process of the vertical pump unit, the load increases at low speed. The thrust bearing bears the weight of all rotating parts and a small part of axial water thrust. At this time, the thickness of oil film on the tile surface is very small, the lubrication performance is poor, the friction resistance is large, the bearing face is damaged greatly, and the unit should not stop too often. (7) the higher the viscosity of lubricating oil, the greater the bearing capacity of thrust bearing. When the load of thrust bearing is fixed, the greater the viscosity of lubricating oil, the greater the thickness of oil film on the tile surface and the better the lubricating performance.
【学位授予单位】：扬州大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TH133.3

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