计及复杂换位结构的百万千瓦级汽轮发电机定子流固耦合传热研究

Study of Fluid-solid Coupled Heat Transfer in Stator of Million-kilowatt-class Turbo-generator With Complex Transposition Structure

百万千瓦级汽轮发电机的定子绕组通常采用多根空、实心股线并绕的复杂编织换位结构,针对尺寸相差悬殊的复杂结构使得其定子流固耦合模型的数值求解存在网格数量多、容易出现奇异解的难点问题,该文提出三维区段式流固耦合网格划分方法,根据不同区段股线的结构及传热特点,通过非均匀网格划分方法大大降低求解模型的网格数量,实现计及复杂换位结构的定子流固耦合模型的数值求解,并通过一台124万kW水氢氢冷汽轮发电机的短路型式实验进行验证。在此基础上,提出定子绕组的新型交叉换位方法并与传统换位方法的温度进行对比,结果表明,新型交叉换位方法使定子绕组股线以及绝缘的温度分布更加均匀,并且能够有效降低定子绕组最高温度。

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.