空冷汽轮发电机转子风道结构对传热的影响

The Effect of Geometry Factors on Heat Transfer of Rotor’s Cooling Duct of Large Turbo Generator With Air-coolant

大型空冷汽轮发电机转子通风道中,副槽的几何形状、径向通风沟的条数及间距、槽楔出风口直径等几何量,直接影响风道内空气的流动及传热特征。转子组件的可靠性及寿命依赖于空冷通道的散热能力。因而,了解发电机转子风道中各空气区域内的速度分布、传热系数变化及温度分布是非常重要的。为了能够得到转子截面较均匀并且最高温度值较低的优化温度分布,文中在150MW空冷汽轮发电机转子实验研究基础上,改变副槽的几何形状、径向通风沟的条数及间距、槽楔出风口直径等几何量,采用有限体积法求解转子本体及通风道内空气的传热及紊流流动等二维离散方程组。研究结果表明,在相同的入口风速下,两条径向风沟比一条径向风沟时散热效果好,并存在最佳中心距。

In rotor＇s cooling duct of large turbo generators, the configuration parameters of sub slot, the number of winding＇s cooling ducts and center distance of them, and the diameter of slot wedge directly affect the flow and heat transfer characteristics of air in duct. The reliability and the life period of rotor components depend on the heat transfer ability of the cooling system. Therefore, the knowledge of distribution of air velocity, surface heat transfer coefficient and temperature inside all the air regions in electric machine is very important. To obtain more uniform temperature distribution and relative lowest temperature over cross section of the rotor, on the basis of test data of a given example of a 150MW turbo generator with air coolant, numerical solution of two dimensional modelling equations of air turbulent flow and heat transfer in and between cooling duct and rotor were carried by the Finite Volume Method at condition of varying configuration parameters of sub slot, the number of winding＇s cooling ducts and center distance of them, and the diameter of slot wedge. The results show that the ability of cooling of two radius ducts is better than one duct, and optimum center distance is exist between two ducts at condition of the same inlet velocity.