【作者】 宋厚彬；

【导师】 李伟力；

【作者基本信息】 哈尔滨理工大学 ， 电机与电器， 2014， 博士

【摘要】 灯泡贯流式水轮发电机是灯泡贯流式水电站的主体设备，它具有结构尺寸大、电磁负荷高等特点，是目前水电站大中型水轮发电机的首选。然而，水轮发电机发热一直是影响水轮发电机组安全运行的一个主要因素，发电机通风冷却系统结构的设计是否合理，能否满足发电机实际运行的需要，成为要研究和解决的重点问题之一。本文基于流体力学与传热学的基本理论，针对流场和温度场多场共同作用下的灯泡贯流式水轮发电机通风结构开展了理论研究工作。通过对灯泡贯流式水轮发电机轴径向通风结构在冷却介质是空气的情况下的温度场和流场，进行了全三维数值模拟及分析，研究了传统结构下的各场量分布情况以及耦合相关性。并探究了发电机转子支架轴径向安放角对流场和温度场的影响，以及发电机转子支架安放位置的变化对发电机轴功率的影响，揭示了转子支架轴径向安放角变化，冷却气体流量变化时定子和转子及铁心和绕组上的温度分布特性。通过对传统结构灯泡贯流式水轮发电机轴径向通风结构的数值计算结果与实际运行机组测点数据的比较表明，采用热场（温度场）、流场之间相互耦合的数值计算方法所得结果是可靠的。同时研究结果也揭示了传统设计轴径向通风冷却结构在定子及绕组之间通风孔间隙处存在有明显局部高温的原因。本文提出了发电机转子支架轴径向安放角的概念，利用风机的设计方法，采用基于涡流理论、叶素理论的Wilson方法对传统发电机转子支架进行了重新设计，并以MATLAB语言为工具编写叶片设计的计算程序；为便于叶片加工制造，又对叶片径向安放角与轴向安放角进行修正，输出各参数的计算结果。通过对叶片径向安放角与轴向安放角的单相匹配的数值研究发现，当叶片轴向安放角=0时，随着径向安放角的增加发电机内部最高温度有所下降，但数值较小；当叶片径向安放角=0时，随着轴向安放角增加，发电机内部最高温度有所下降，较仅仅改变径向安放角时下降的数值有所增加，但整体的温度下降仍然不够明显。通过对叶片径向安放角与轴向安放角的双向匹配的数值研究发现，在不采用风机强制通风时轴径向支架安放角=6，=6°时通风冷却结构的流场流动更为顺畅、流场分布更加合理，冷却介质的轴向流速和径向速度有最佳匹配值。发电机转子在相同转速下，优化后径向通风结构使得定子及周围流体所传递与辐射的能量有所减小，最终使得温度场内最高温度与高温区域均有所减小，最高温度较传统结构在通风量相同时降低约15℃-18℃，冷却效果明显；而叶片优化设计后，发电机轴功率的消耗不超过1‰。通过对最优转子支架轴径向安放角组合方案，非定常模式下多场耦合的研究，更加深入揭示了发电机内部流场压力、温度场及转子轴功率的时域特性。从各个监测点上参数变化规律，再一次验证了添加轴径向安放角要比传统无安放角通风结构的冷却效果要好，这种后弯式通风支架结构更有利于冷却空气在轴向和径向的流动，在保证水轮发电机正常运行情况下能减少风机的使用数量；由轴功率和支架监测点的振动特性可知，优化后的结构对支架材料并未提出更高要求，更符合通风结构的使用。更多还原

【Abstract】 As the main equipment of bulb tubular hydropower station, flow-bulbhydrogenerator has many advantage such as the large structure size and highelectromagnetic load, so at present it is the first choice of the large and medium-sized turbine generator in the hydropower station. However, hydrogenerator feverhas been one of the main factors affecting the safety operation of hydroelectricgenerating. Whether the structure design of generator ventilation cooling systemis reasonable and can meet the needs of the generator operation, has become theemphasis and difficulty to understand and solve.Based on the fluid mechanics and heat transfer, this paper carried outresearch of several common ventilation structures of bulb tubular turbinegenerator under electric field, fluid field and temperature field. For the bulbtubular turbine generator axial-radial ventilation structure which cooling mediumis air, the3D numerical simulation and analysis method was adapted and thetraditional structure of the field distribution and the coupling correlation isstudied. The influence which setting angle of the generator rotor bracket axial-radial carried on the flow field and temperature field was explored and theinfluence which the generator rotor bracket setting angle carried on the generatorshaft power was also explored. The temperature distribution of the stator, rotorand core winding as the cooling gas discharge changed flow was revealed.Compared the numerical results with actual testing point data for traditionalaxial-radial ventilation structure for bulb tubular turbine generator, this paperfound that the thermal field, temperature field, flow field numerical calculationmethod of the multi-field coupling between the results is reliable. At the sametime the calculation results also revealed the reason for the local hightemperature in the clearance between the stator and coil for the traditional axial- radial ventilation cooling structure.In this paper, the concept of generator rotor bracket axial-radial SettingAngle was put forward on the basis of the working principle of the fluidmachinery fan for reference. Based on the vortex theory, blade element theory ofWilson method the traditional generator rotor bracket was designed using fandesign method. The blade design calculation was programmed by means ofMATLAB language. For convenience of blade manufacturing, the blade radialSetting Angle and axial Angle correction was updated and results was output.Through the study of unilateral matching relationship of radial SettingAngle and axial Setting Angle of blade, we can found that when the blade axialAngle=0, with the increasing of radial setting Angle generator within thehighest temperature declined, but the value is small; When radial blade Angle=0, with the increasing of axial setting Angle, the highest temperaturegenerator internal also fell, but the temperature drop of the whole is still notenough.Through the study of bilateral matching relationship of Setting Angle andaxial Setting Angle of blade, we can find that when the blade axial Angle=12and=12with forced ventilation fan ventilation cooling structure of flowfield flows was more smoothly, flow field distribution was more reasonable andit means the axial velocity and radial velocity of cooling medium has the bestmatch. As Generator rotor operated at the same speed, the optimized radialventilation structure makes the stator and the surrounding fluid transmission andradiation energy reduced, eventually reduced the highest temperature and hightemperature area were also reduced. And the highest temperature compared withtraditional structure about15DHS in ventilation rate phase at the same timereduce15℃-18℃, the cooling effect was obvious; And after this kind ofstructure of blade optimization design, the generator shaft power consumption isnot total1‰.Through the research of the optimal combination scheme of Setting Angle ofrotor bracket axial-radial put more unsteady mode field coupling, the studyfurther revealed the internal electric field generator, flow pressure, temperaturefield and the time domain characteristics of the rotor shaft power. Parameterschange rule of the monitoring point verified again add axial-radial setting Angle than conventional ventilation without setting Angle structure of the cooling airflow better. And the bending type blade ventilation structure is moreadvantageous to the flow of cooling air in the axial and radial, meanwhile it caneliminate the heat as much as possible, under the condition of ensure the normaloperation of hydraulic generator, unit can reduce the amount of use fan.更多还原