汽轮发电机转子风路堵塞时的温度场数值分析

Numerical analysis of turbo generator rotor temperature field on partial vents blocked

大型汽轮发电机结构紧凑,气隙狭小,其运行的安全可靠性依赖于冷却系统的散热能力。因而,若其冷却系统维护不当,发生通风道堵塞故障,造成的后果不堪设想。为详细了解风道堵塞对转子流场及温度场的影响,以一台150 MW空内冷汽轮发电机为例,建立转子径向通风道发生堵塞时的二维流动与传热物理和数学模型;同时给出边界条件和假设条件,采用有限体积法对转子发生堵塞时的温度场、流体场进行数值计算,并对不同堵塞程度下的转子温度场进行比较;最后分析总结了一条转子径向通风沟堵塞时,堵塞严重程度与转子温度分布之间的变化规律。研究表明,径向通风沟未发生全堵时对转子温度影响较小。一旦发生全堵,即使只堵塞一条径向通风沟也会对发电机造成严重破坏。因此,加强发电机转子风路故障方面的研究非常有必要。

The large turbo generators all have compact structure and small gap.So its safety and reliability mainly depends on heat-sinking capability of cooling system.Therefore,if its cooling system is maintained improperly and leads to ventilation ditch blocked,the consequences would be disastrous.To know more about the influence of ventilation ditch blocked on rotor＇s velocity and temperature field,2-D mathematical and physical model of flow and heat transfer inside the rotor radial ventilation ditch with blocking issue of a 150MW turbo generator with air coolant are established in this paper.At the same time,according to boundary conditions and hypothesis,the 2-D rotor temperature field and fluid field are numerically calculated by finite volume method,and different temperature field in different blocking issue is analyzed.At last,the relationship between rotor temperature and the extent of blocking is analyzed and summarized.Studies show that,radial ventilation ditch blocked do not cause severe damage to the generator until they are completely blocked.Therefore,the knowledge of ventilation ditch fault is essential.