采用热路方法和三维有限元方法计算三峡水轮发电机三维热网络热阻参数的研究

为采用三维热网络计算三峡水轮发电机温度场,本文给出了一个单元区域的定子铁心段和定子端部的三维非线性热网络结构,分别采用三维有限元方法和热路方法计算了定子铁心段和定子端部各个节点之间的热阻参数,分析了两种方法对于三维热网络热阻参数计算相对误差,认为热网络的节点之间含有绝缘区域的热阻不适用热路法计算,而应采用三维有限元计算.三峡发电机定子热网络中,有近半数的节点之间含有绝缘区域的热阻.且通过对定子端部绕组三维温度分布的计算表明,场参数三维非线性热网络模型计算值比路参数三维非线性热网络模型计算值与三维有限元模型计算值的更接近.因此,有必要采用三维有限元法计算三维热网络的热阻参数.

Comparing Between 3D Finite-element Method and Thermal-circuit Method of Calculating Thermal-resistances in the Thermal Field of Three-gorge Hydrognerator

In order to calculate the thermal-field of Three-gorge hydrogenerator using 3D thermal-network,this paper presents the structure of 3D thermal-network on an unit of stator core and an unit of stator ending.The parameters of thermal-resistances between nodes of stator core and stator ending are calculated by using 3D finite-element method and thermal-circuit method.And the relative errors of calculation gotten from these two methods are analyzed.The analysis results show that the thermal resistances among nodes,which have insulation region,are not fit to be calculated by the thermal-circuit method,but the 3D finite element method.This kind of thermal resistances occupied nearly half of all thermal resistances in 3D thermal network of Three-gorge hydrogenerator.And the calculation results of 3D thermal-network with the parameters calculated by using 3D finite-element method are closer to the calculation results of 3D finite-element method than that of thermal-circuit method through calculating of 3D thermal-field of stator ending-winding.So,it is necessary to calculate the thermal resistances by using 3D finite element method.