空冷汽轮发电机定子内流体流动与传热的数值模拟

发布时间：2018-03-04 13:53

本文选题：空冷汽轮发电机　切入点：定子通风冷却系统　出处：《华中科技大学》2014年硕士论文　论文类型：学位论文

【摘要】：大型汽轮发电机在运行过程中，由于电磁及机械损耗会使电机内部产生大量热量，如果不能有效地将这些损耗所产生的热量导散出去，可能造成发电机的温升或局部温升过高，直接影响发电机的运行安全性和寿命。特别是对于大型空冷汽轮发电机，其通风冷却系统是电机安全稳定运行的重要保障。因此，对汽轮发电机通风冷却系统内流动与传热情况进行研究具有十分重要的意义。本文首先根据320MW空冷汽轮汽轮发电机定子通风冷却系统特点，分别建立了电机定子通风系统内流体场模型和定子内流动与传热耦合模型，并给出了相应的数学物理描述。对额定工况下电机定子通风系统流体场模型采用CFD软件进行了数值模拟计算，，得到了通风系统内详细的流动特性即压力、流速、流量分布，并在此基础上，对电机定子流体场与温度场进行了耦合求解，分别得到了通风系统和电机铁心及线棒的温度分布，并对其流动传热特性进行了详细的分析，为电机通风系统设计优化以及电机实际运行中的监测提供了参考依据。为研究电机通风系统风量分配和定转子气隙径向高度对电机内流动与传热的影响，分别对转子气隙入口与定子背部风室入口不同配风工况以及不同气隙径向高度的结构模型方案进行了数值计算，在电机通风系统风量分配优化和结构优化方面进行了初步研究，并得到了一些有益的结论。通过数值模拟研究，对汽轮发电机定子通风冷却有了更加深入的认识，数值计算得到的结论为电机通风系统设计优化及运行监测提供了一些参考和建议。
[Abstract]:During the operation of a large turbogenerator, the electromagnetic and mechanical losses will cause a large amount of heat in the motor. If the heat produced by these losses cannot be effectively transported out, the temperature rise of the generator may be too high or the local temperature rise may be too high. Especially for large air-cooled turbogenerator, the ventilation cooling system is an important guarantee for the safe and stable operation of the generator. It is of great significance to study the flow and heat transfer in the ventilated cooling system of turbogenerator. Firstly, according to the characteristics of stator ventilation and cooling system of 320 MW air-cooled turbogenerator, the fluid field model in stator ventilation system and the coupling model of flow and heat transfer in stator are established in this paper. The mathematical and physical description is given. The flow field model of motor stator ventilation system under rated working condition is numerically simulated by CFD software, and the detailed flow characteristics, i.e. pressure, velocity and flow distribution, are obtained. On this basis, the coupled solution of the stator fluid field and temperature field of the motor is carried out, and the temperature distribution of the ventilation system, the motor core and the wire rod are obtained respectively, and the flow heat transfer characteristics are analyzed in detail. It provides a reference for the optimization of the design of the motor ventilation system and the monitoring in the actual operation of the motor, and studies the effect of the distribution of air volume in the motor ventilation system and the radial height of the stator and rotor air gap on the flow and heat transfer in the motor. The structural model schemes of rotor air gap inlet and stator back air chamber inlet under different air distribution conditions and different air gap radial height are numerically calculated, and the air volume distribution and structure optimization of motor ventilation system are studied preliminarily. Some useful conclusions are obtained. Through the research of numerical simulation, a deeper understanding of stator ventilation cooling of turbogenerator is obtained, and the conclusion obtained by numerical calculation provides some references and suggestions for the design optimization and operation monitoring of motor ventilation system.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM311

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