Thermal-Elastic Deformation Analysis And Performance Estimate Of Heavy-duty Bearing Of Nuclear Power Turbine

As a new kind of energy, nuclear power is developing rapidly in our country. The capacity of nuclear power turbine is also increasing rapidly, and 1200 MW nuclear power turbines have been the main turbine units. As the main part of the system of turbine rotor, the size and load of the bearing for low pressure cylinder are increasing significantly. So it’s important to research the influence of elastic and thermal deformation to lubrication characteristics.This thesis is based on the heavy-duty journal bearing of 1200 MW nuclear power turbine. According to the structural characteristics, the way to lubricate, load condition and working condition of this bearing, by the software ANSYS, a separate and coupling analysis are made to the elastic and thermal deformation of this bearing on the condition of rated load and rotate speed. Then, the influence of elastic and thermal deformation to dynamic and static characteristic parameters is analysed. Compared with considering the hydrodynamic effect, if elastic deformation is also considered, the analysis results for bearing performance will be different: the minimum oil thickness is smaller, the quantity of flow is larger, the temperature rise is smaller, and the maximum oil film pressure and temperature are slightly higher; the stiffness and damping coefficients are bigger. This changing trend is similar with increasing the clearance ratio. If bearing performances are analysed by the theory of thermohydrodynamic lubrication, compared with the calculation result of no-considering the deformation, the results of static characteristic parameters are the same as above: the minimum oil thickness is smaller, the quantity of flow is larger, the temperature rise is smaller, the maximum oil film pressure and temperature are slightly higher. But horizontal main stiffness is smaller, vertical main stiffness is slightly bigger, and the four damping coefficients are smaller. This changing trend of static characteristic is similar with increasing the clearance ratio.This thesis presents a compensation design for bearing structure which regards the actual inner surface of pad as the target of design after considering elastic and thermal deformation when bearing is working. When machining the bearing, the technique of cold machine is used to make the inner of pad be a no-round surface and the outer face be round. So it can compensates the influence of elastic and thermal deformation to hydrodynamic effect. Overall, this thesis provides engineering solutions for the design of the heavy-duty bearings.