Numerical analysis of end part temperature in the turbogenerator end region with magnetic shield structure under the different operation conditions

Due to the serious overheating problem of end parts in the large turbogenerator end region, accurate calculation of end-part temperature has become a key design factor. In this paper, 3-D fluid and thermal coupling model in the end region of 1250 MW turbogenerator are given. The loss values gained from 3-D transient electromagnetic field calculation are applied to the solving end region as heat sources. Pressure value of fan outlet and fluid velocities of end region inlets from flow network calculation are applied to the solving end region as boundary conditions in the 3-D fluid and thermal coupling analysis model. The fluid flow and temperature distribution of end parts in the end region of large turbogenerator with magnetic shield structure are studied under the different operation conditions. The distribution of fluid velocity in the ventilation duct of stator end core is obtained. The temperature distribution laws of stator-end copper coils, screen plate, finger plate, press plate, and magnetic shield are researched under the different operation conditions. The location of the highest temperature point in the turbogenerator end region with magnetic shield structure is determined. The accuracy of numerical calculation is validated by experimental measured values.