Abstract
The operating stability of guide bearings under load fluctuations in giant hydro turbines is a critical issue. As a crucial component supporting rotating machinery and enduring radial forces, guide bearings suffer from problems including rapid wear and unstable operation. In this study, a three-dimensional thermo-hydrodynamic model of the 1000 MW giant Francis turbine unit guide bearing is applied to analyze the oil film lubrication characteristics and flow in a turbine tank. The effects of installation deviations on the upper guide bearing are analyzed, and the results demonstrate that the cooler has little effect on the pressure and the velocity distribution within the oil film. A Q-criterion is defined to analyze the flow in the tank, and the results indicate that the high-velocity and strong-vortex regions are mainly distributed within the rotating oil line and the oil film region. In the oil tank, the velocity and vorticity are relatively low despite the presence of chaotic spiral vortices. The maximum values of the temperature and pressure within the oil film and the unbalanced radial force increase with the level of deviation. As a result, the temperature distribution becomes more uneven. The conclusions obtained in this paper can be used to guide engineering practice.