大型发电机定子绝缘老化后非线性温度场计算

为了更准确地计算大型发电机内的温度分布，给出了直角坐标系下三维热传导方程及其等价泛函，并给出了计算区域内相应的边界条件，同时推导了采用牛顿拉夫逊方法求解非线性温度场的迭代格式。以一台凸极同步发电机为例，建立了径向通风沟内流速、散热系数与壁面温度的非线性数学模型，采用六面体八节点单元计算了该台电机定子通风沟流场非线性变化情况下的三维温度场，用数值模拟的方法分析了上述流场非线性情况下绝缘老化脱壳后的定子温度场，得出了相应的定子各部分温度变化规律及径向通风沟内表面散热系数和风速的分布规律，将计算结果与实测值及线性情况进行了比较，计算精度满足工程需要，为电机运行过程中的温度监测和热故障诊断提供了理论依据。

Calculation of nonlinear stator temperature field after insulation aging for large generator

For accommodating the need of development of modern machines production, temperature distribution in large generator should be calculated better and more truly. The 3D equations of heat conduction as well as equivalent functional equations under rectangular coordinate system are presented. The boundary conditions of solution region are given. The iterative formula of Newton Raphson method are deduced. A salient pole synchronous generator is taken for an example to be calculated and nonlinear mathematics model of air speed, convection coefficient and wall side temperature in radial ventilating grooves is built. 3D Isoparametric Finite Element Method is applied to compute the 3D temperature field while flow field in stator ventilating grooves is a nonlinear field. At the same time, numerical simulation method is used to analyze the stator temperature field after insulation aging and the trend of temperature variation in each stator part are determined. Finally, the calculated results are compared with measured results and the accuracy meet the need of engineering application, which lay a theoretical foundation for on line temperature monitoring and heat faults diagnosing.