Study of Fluid-solid Coupled Heat Transfer in Stator of Million-kilowatt-class Turbo-generator With Complex Transposition Structure
In stator windings of million-kilowatt-class turbo-generators,the complex transposition structure with many parallel hollow strands and solid strands is usually adopted.Addressing the challenging issue of the numerical solution of the stator fluid-solid coupling model,which suffers from a large grid count and susceptibility to singular solutions due to the intricate structure with vastly varying sizes,this paper proposes the three-dimensional segmental fluid-solid coupling grid division method.The proposed method can significantly reduce the number of grids in the solution model by utilizing a non-uniform grid division method based on the structure and heat transfer characteristics of strands in different segment.As a result,it enables numerical solution of the stator fluid-solid coupling model considering the complex transposition structure.The proposed method is verified by the short circuit type test data of a 1.24 million-kilowatt-class water-hydrogen-hydrogen-cooled turbo-generator.On this basis,a new cross-transposition method for stator windings is proposed,and the temperature is compared with that of the traditional transposition method.The results demonstrate that the temperature distribution of strands and insulation of stator windings is more evenly and the maximum temperature of stator windings can be reduced effectively for the new cross-transposition method.
million-kilowatt-class turbo-generatorstatorcomplex transposition structurefluid-solid coupling modelheat transfer