基于纵向涡发生器的水轮发电机定子通风系统CFD优化研究
发布时间：2018-08-16 13:03
【摘要】：近年来水力发电行业不断进步,水力发电需求逐渐增大,我国的水电总装机容量持续增高。水轮发电机作为水力发电过程中的重要设备,其设计和运行也越来越受到重视。水轮发电机运行中的发热问题直接关系到它的运行可靠性与使用寿命,因此通风散热一直是水力发电设备研究的关键问题之一。定子通风系统是水轮发电机通风散热系统的重要组成部分,其结构设计的合理与否以及内部冷却气体流动速度和温度的分布直接关系到水轮发电机的正常运行。本文基于计算流体力学和传热学的基本理论建立了灯泡贯流式水轮发电机定子通风系统多场耦合计算模型,针对水轮发电机定子通风系统的流场和温度场分布及其耦合进行深入研究并通过在定子通风沟内·设置纵向涡发生器改进定子通风系统结构,增强散热效果。本文利用三维造型软件UG建立了定子通风系统模型,通过ICEM CFD对三维模型进行网格划分之后导入流体流动分析软件Fluent中计算分析定子通风系统的流场和温度场,了解系统整体与局部的风速和温度分布以及高温区域的位置,并研究了入口风速对定子通风系统温升的影响。研究表明系统内的最高温度出现在定子线圈,流体部分的高温出现在定子线圈后面的轭部区域。入口风速在一定程度内增大会导致系统温升迅速降低,超过一定范围后入口风速继续增大温升的降低不再明显。本文中基于强化散热理论提出了在定子通风沟中设置纵向涡发生器来改善定子通风系统散热效果的方法,并对纵向涡发生器的设置方案进行介绍,研究了纵向涡发生器增强散热的机理和影响因素包括冲角,高度以及径向安装位置等。本文提出了最高温度降低量和对比阻力系数两个优化设计的标准来进行对比。在定子通风系统中设置纵向涡发生器后其下游区域形成明显的纵向涡增强换热。通过对纵向涡发生器优化因素的分析发现,在定子通风系统齿部中间靠近入口处设置高度为5mm,冲角为45°的纵向涡发生器增强散热效果最佳,系统内部的温度分布相对比较均匀。本文的研究为水轮发电机通风系统特别是定子通风系统的设计提供了一定的参考。
[Abstract]:In recent years, with the continuous progress of hydropower industry, the demand for hydropower is increasing gradually, and the total installed capacity of hydropower in China continues to increase. As an important equipment in hydroelectric power generation process, the design and operation of hydrogenerator are paid more and more attention. The heating problem of hydrogenerator is directly related to its reliability and service life, so ventilation and heat dissipation is always one of the key problems in the research of hydropower equipment. Stator ventilation system is an important part of hydrogenerator ventilation and heat dissipation system. Whether the structure design is reasonable or not and the distribution of cooling gas flow velocity and temperature directly affect the normal operation of hydrogenerator. Based on the basic theories of computational fluid dynamics and heat transfer, a multi-field coupling calculation model for stator ventilation system of bulb tubular hydrogenerator is established in this paper. The distribution and coupling of flow field and temperature field in stator ventilation system of hydrogenerator are studied in depth. The structure of stator ventilation system is improved by setting longitudinal vortex generator in stator ventilation ditch and the heat dissipation effect is enhanced. In this paper, the stator ventilation system model is established by using the three-dimensional modeling software UG, and the flow field and temperature field of the stator ventilation system are calculated and analyzed by introducing the fluid flow analysis software Fluent after the three-dimensional model is meshed by ICEM CFD. The global and local wind speed and temperature distribution and the location of the high temperature region are studied. The influence of the inlet wind speed on the temperature rise of the stator ventilation system is studied. The results show that the highest temperature of the system occurs in the stator coil and the high temperature of the fluid part appears in the yoke area behind the stator coil. When the inlet wind speed increases to a certain extent, the temperature rise of the system will decrease rapidly, but the decrease of the inlet wind speed will continue to increase and the temperature rise will not be obvious when the inlet wind speed exceeds a certain range. Based on the theory of enhanced heat dissipation, this paper puts forward a method of setting longitudinal vortex generator in stator ventilation ditch to improve the heat dissipation effect of stator ventilation system, and introduces the setting scheme of longitudinal vortex generator. The mechanism and influence factors of the longitudinal vortex generator are studied, including the angle of incidence, the height and the position of the radial installation. In this paper, two optimal design criteria, maximum temperature reduction and contrast resistance coefficient, are put forward for comparison. The longitudinal vortex-enhanced heat transfer is formed in the downstream region of stator ventilation system with longitudinal vortex generator. Through the analysis of the optimization factors of the longitudinal vortex generator, it is found that the longitudinal vortex generator with a height of 5 mm near the entrance of the stator ventilation system teeth and an angle of incidence of 45 掳has the best effect of enhancing heat dissipation, and the temperature distribution in the system is relatively uniform. The research in this paper provides a certain reference for the design of hydrogenerator ventilation system, especially stator ventilation system.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM312
本文编号：2186062
[Abstract]:In recent years, with the continuous progress of hydropower industry, the demand for hydropower is increasing gradually, and the total installed capacity of hydropower in China continues to increase. As an important equipment in hydroelectric power generation process, the design and operation of hydrogenerator are paid more and more attention. The heating problem of hydrogenerator is directly related to its reliability and service life, so ventilation and heat dissipation is always one of the key problems in the research of hydropower equipment. Stator ventilation system is an important part of hydrogenerator ventilation and heat dissipation system. Whether the structure design is reasonable or not and the distribution of cooling gas flow velocity and temperature directly affect the normal operation of hydrogenerator. Based on the basic theories of computational fluid dynamics and heat transfer, a multi-field coupling calculation model for stator ventilation system of bulb tubular hydrogenerator is established in this paper. The distribution and coupling of flow field and temperature field in stator ventilation system of hydrogenerator are studied in depth. The structure of stator ventilation system is improved by setting longitudinal vortex generator in stator ventilation ditch and the heat dissipation effect is enhanced. In this paper, the stator ventilation system model is established by using the three-dimensional modeling software UG, and the flow field and temperature field of the stator ventilation system are calculated and analyzed by introducing the fluid flow analysis software Fluent after the three-dimensional model is meshed by ICEM CFD. The global and local wind speed and temperature distribution and the location of the high temperature region are studied. The influence of the inlet wind speed on the temperature rise of the stator ventilation system is studied. The results show that the highest temperature of the system occurs in the stator coil and the high temperature of the fluid part appears in the yoke area behind the stator coil. When the inlet wind speed increases to a certain extent, the temperature rise of the system will decrease rapidly, but the decrease of the inlet wind speed will continue to increase and the temperature rise will not be obvious when the inlet wind speed exceeds a certain range. Based on the theory of enhanced heat dissipation, this paper puts forward a method of setting longitudinal vortex generator in stator ventilation ditch to improve the heat dissipation effect of stator ventilation system, and introduces the setting scheme of longitudinal vortex generator. The mechanism and influence factors of the longitudinal vortex generator are studied, including the angle of incidence, the height and the position of the radial installation. In this paper, two optimal design criteria, maximum temperature reduction and contrast resistance coefficient, are put forward for comparison. The longitudinal vortex-enhanced heat transfer is formed in the downstream region of stator ventilation system with longitudinal vortex generator. Through the analysis of the optimization factors of the longitudinal vortex generator, it is found that the longitudinal vortex generator with a height of 5 mm near the entrance of the stator ventilation system teeth and an angle of incidence of 45 掳has the best effect of enhancing heat dissipation, and the temperature distribution in the system is relatively uniform. The research in this paper provides a certain reference for the design of hydrogenerator ventilation system, especially stator ventilation system.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM312
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