Influence of Magnetic Permeability of the Press Plate on the Loss and Temperature of the End Part in the End Region of a Turbogenerator

Press plates are widely used in the end region of turbogenerators. However, due to the effect of magnetic field leakage from the end region, the eddy current losses of the copper screen and press plate will result in the copper screen and press plate having a high temperature under the rated load condition. In this paper, the influence of the magnetic permeability of the press plate on losses and temperature of the end region is researched in turbogenerators. Three-dimensional (3-D) fluid and thermal mathematic and physical models of the turbogenerator end region are established. Under different magnetic permeability values of the press plate, a 3-D transient electromagnetic field in the turbogenerator end region is calculated, and the obtained losses of the end parts are treated as heat sources. Fluid network equations are calculated, and the obtained fluid velocity and pressure values are applied to the end region as boundary conditions. After solving the fluid and thermal equations, fluid velocity around the surface of the end parts is obtained under the rated load condition. The temperature distribution of the end parts is determined for different magnetic permeability values of the press plate. The calculated temperature results agree well with the test data.