大型汽轮发电机转子温度场计算

Temperature Field Calculation for Rotor of Large Turbine Generator

以一台空冷汽轮发电机作为研究对象,根据传热学原理,通过建立转子绕组槽绝缘与槽楔的转子圆周1/4三维有限元模型,给出了求解域内的基本假设及相应的边界条件。根据气隙磁密的提取,计算出额定工况下转子表面杂散损耗,以转子绕组电阻损耗和表面杂散损耗作为热源,采用解析法计算得到转子通风沟表面散热系数,并以此为基础,将计算得到的各项损耗值及散热系数作为温度场求解条件,对汽轮发电机转子直线段部分三维温度场进行计算,得到了发电机额定负载运行时转子温度场分布。

Taking an air-cooled turbine generator as a research object, this paper gives the basic assumptions in solving region and corresponding boundary conditions based on heat transfer theory by establishing a 3D finite-element model of 1/4 the rotor circumference inclu- ding slot insulation and slot wedge of rotor winding. The rotor surface stray loss of motor under the rated load condition is caleulated according to the obtained air-gap flux density. Taking the copper loss of rotor winding and stray loss on rotor surface as a heat source, the surface thermal coefficient of rotor ventilation grooves are obtained by analytical method. On this account, the 3D temperature fields of straight line part of generator rotor are calculated by using all losses and heat release coefficient calculated above as the solving condition. Thus, the rotor tempera- ture field distribution of generator operated at the rated load is obtained.