Hydrodynamic Lubrication Analysis And Experiment Development Of A Nuclear Reactor Coolant Pump Thrust Bearing

Hydrodynamic bearing form a layer of oil film pressure to support the load when it is working. It has been widely used in various types of large rotating machinery equipment such as steam turbine, pump. Thrust bearing can only support axial load in the system, the working status of its operation conditions directly affect the performance of the whole system.Nuclear main pump, the rotating parts of nuclear power in the system, are required to working right, when the nuclear power system are suddenly stopped, because of the inertia and then to make the coolant continue flow through the reactor core, taking away the heat and preventing from burning. The the hydrodynamic lubrication research of the dynamic pressure thrust bearing is mainly to study the pressure field and temperature field of dynamic fluid field.Since the nuclear coolant pumps are so important and their operating conditions are so demanding, the study of hydrodynamic lubrication for bearing is essential. In this thesis, the bearing for main pump is tilting pad thrust bearing, which supports the axial load. The main work of this paper are as follows:1) A kind of tilting pad thrust bearing which is used to support the heavy load with high speeds is introduced, the maximum speed up to 1500 rpm, normal axial load up to 794 kN.2) Describes the overall structure, including the structure of the inner key parts, and the working principle of the main pump. A mathematical model of tilting pad thrust bearing was established, including Reynolds equation, the bearing oil film thickness equation, energy equation, elastic deformation equation and the lubricating oil viscosity temperature relationship, as well as their boundary conditions.3) A test rig was built and the 72 hour long program experiment was carried out. In the whole operation process the bearing test rig was stable, normal and no large fluctuations.Temperature distribution of two main thrust bearing at the same point, the inlet and outlet oil temperature and inlet oil flow, which provides the basis for setting the parameters for the simulation, was measured. Comparing the measured temperature and theoretical temperature from simulation analysis, it can verify the correctness of the simulation. Whether the temperature of two main thrust pad is closed, are the key factors to evaluate the success of this experiment.4)The three-dimensional numerical simulation of oil film on the pad was established using FLUENT software. The numerical simulation includes temperature field, pressure field and the oil film velocity field. The oil film bearing capacity and load size are consistent.Comparing the measured temperature and theoretical temperature from simulation analysis,verify the correctness of the simulation. Finding out the effect of changing fulcrum position of pad on the lubrication performance of bearing, obtain the optimum bias point position.