大型空冷汽轮发电机定子端部温度场与流体场的计算与分析

Temperature and Fluid Flow Field Calculation and Analysis of Stator End of Air Cooled Turbo-generator

根据200MW大型空冷汽轮发电机通风系统内流体流动与传热的特点,建立定子端部和多风路通风系统三维流动与传热耦合计算的数学模型和物理模型,并给出求解域相应的边界条件及假设条件,采用有限体积法对流体场和温度场控制方程进行耦合计算,可以得到定子端部流体出口处流量及端部绕组、压板周围的流体速度空间分布特性,从而确定多风路求解域中各风路入口的边界条件及端部各结构件的散热系数。分析了端部绕组、压板周围不同散热系数下,定子绕组、铁心、压指和压板温度的分布情况。将耦合场计算结果与实测结果进行分析,结果表明,端部计算模型计算出的各风路风量可作为多风路模型计算中各入口的流量边界条件,也表明多风路模型中的基本假设是合理的。结论对大型电机定子端部散热系数选择提供方法和依据。

Considering the characteristics of fluid-flow and heat-transfer of a 200 MW air cooled turbo generator, the 3-D mathematical and physical model of stator end and multipath ventilation system for fluid and temperature coupling analysis were established, which were calculated numerically by using finite volume method （FVM）, based on some corresponding boundary conditions and assumptions. In this process, the outlet flow rate of stator end and the distribution characteristic of fluid velocity around stator end windings and pressure plate were solved, so the boundary conditions of each inlet in the solving domain and heat transfer coefficients of stator end parts were determined. Stator winding, iron core, pressure finger and pressure plate temperature distribution were analysized under different heat transfer coefficient of stator end winding and pressure plate. Theoretical approach together with experimental results confirms the validity of the proposed method, including flow distribution obtained by mathematical and physical model of stator end, the boundary conditions of each inlet and assumptions in the model. The conclusion provides important method and theory basis for heat transfer coefficient determination of stator end in large generators.