水污染对径向滑动轴承热弹流润滑的影响

Effects of Water Contamination on Thermal Elastohydrodynamic Lubrication of Journal Bearing

研究润滑油水污染对水轮机滑动轴承弹流润滑的影响。通过实验确定油水混合物的黏度、水的质量分数以及温度三者间的关系;研究在不同含水量油水混合液润滑下滑动轴承的润滑性能,分析滑动轴承从初始状态到达稳定状态过程中轴心轨迹的变化规律,以及轴承到达平衡位置时各润滑特性参数的分布,包括液膜流体压力、最大液膜压力、液膜厚度、最小液膜厚度、液膜温度等。结果表明,随着含水量的增加,油水混合物的黏度增加,且变化明显,而润滑油的密度、比热容以及导热系数虽增大,但变化并不大;各种因素综合影响的结果,使得轴承液膜承载能力增强,液膜厚度和温度增加,最小液膜厚度增大,最大液膜压力下降。

The effects of water contamination of lubricants on thermal elastohydrodynamic lubrication of journal bearings of water turbo generator were studied. The relationships of viscosity, mass concentration of water and temperature of the oil emulsion were determined with experimental measurements. The lubrication performance of journal bearing with different water concentration was investigated, the orbit of shaft center from initial position to equilibrium position was analyzed, and many lubrication parameters at equilibrium position were studied, including hydrodynamic pressure and maximum hydrody- namic pressure, film thickness and minimum film thickness and temperature. The results show that the viscosity of water-in- oil emulsion is increased obviously with increasing water mass concentration, and its density, specific heat and thermal con- ductivity are also increased, but their changes are not large. For the comprehensive effects of various factors, the bearing load capacity is enhanced, and the film thickness, temperature and minimum film thickness are increased, and the maxi- mum film pressure is dropped.