Coupled Calculation On Stator Fluid Field And Temperature Field Of Turbogenerators

As an important installation of the power grid, the large generators are the direct producer of electrical energy. Improvement of the capacity of turbogenerator will result in the increase of copper loss of the winding bar and thus the rising of the winding's temperature. In order to keep the temperature rise within the allowable range, more efficient cooling technology must be adopted. Enhancing accuracy of the calculation about the flow distribution of the cooling medium and temperature rise can forecast precisely the temperature rise of the turbogenerator's various parts. The temperature rise can be controlled within a permitted scope to ensure the safe and reliable operation of the generator. Therefore, the research on the turbogenerator's ventilation and heating coupling has become more important.The waterway blockage is one of the common malfunctions of the water-hydrogen-hydrogen turbogenerator, so it is easy to detect the fault at an early date when the regulation of the temperature variation is grasped. The heat-transfer process of the water-hydrogen-hydrogen turbogenerator is comparatively complex because its stator core is cooled by the multipath ventilation system and its stator winding is cooled by cooling-water. Thus, the mathematicaland physical models for the 3-D fluid field and temperature field of turbogenerator is established according to the characteristics of the fluid flowing and heat transfer within the cooling system of the large turbogenerator. Meanwhile, the corresponding boundary conditions under some assumptions were given. Through the calculation of 2-D electromagnetic field of the generator, the loss distribution of the stator core can be obtained, and then the coupling calculation of the three-dimensional fluid field and temperature field of the stator's half of the axial length can be carried out by adopting the finite volume method. By using the coupling model in the physical field, the research has been done about the temperature distribution law when the hollow strands of the stator bars are under different blockage malfunctions. Finally, a 220 MW water-hydrogen-hydrogen turbogenerator is taken as an test example, theoretical approach together with measured values confirms the validity of the proposed method. The conclusion in this paper can be used for the design and thermal failure analysis of the large turbogenerator.