水轮发电机组推力轴承油槽内流动及传热特性研究

为解决推力轴承瓦温过高的问题,采用数值模拟方法分析了某水轮发电机组推力轴承内循环冷却系统油槽内润滑油的流动及传热特性。结果表明,靠近镜板处油流速度大,远离镜板位置油流速度小;镜板内缘压力最低,沿着推力轴瓦径向向外压力逐渐增大;初始瓦温、初始油温一定时,随着水温降低,整体油温下降幅度并不大。根据研究结果,对推力轴承内循环冷却系统提出适当增大冷却器U型管直线段的长度、增大冷却器管径、提高冷却水的压力和流量、加大油冷却器铜管间距的改进建议。

Study on Flow and Heat Transfer Characteristics in Thrust Bearing Oil Tank of Hydroelectric Generating Unit

In order to solve the problem of high bearing temperature of thrust bearings,the numerical simulation method is used to analyze the flow and heat transfer characteristics of lubricating oil in oil tank of thrust bearing internal circulation cooling system of a hydro-generator unit.The results show that,(a)the flow rate of oil near the thrust runner collar is large,and the flow rate of oil away from the thrust runner collar is small;(b)the pressure on the inner edge of the thrust runner collar is the lowest,and the pressure increases rapidly outward along the thrust shaft bushing;and(c)when the initial temperature of shaft bushing and the initial oil temperature are constant,the overall oil temperature will not decrease greatly with the water temperature decreasing.According to the research results,some suggestions are put forward for the internal circulation cooling system of thrust bearing,such as appropriately increasing the length of the straight line of the U-type cooler pipe,increasing the diameter of the cooler pipe,increasing the pressure and flow of cooling water,and increasing the distance between cooler copper tubes.