Research On Cooling For Rotor Of Large-capacity Turbo-generator

With the rapid growth of our national economy and the rapid development ofscience and technology, the demand for electricity is increasing and the scales of powerstations are also expanding. Chinese power industry has entered the stage of largecapacity, high parameter, and large power grid since the1980s. Turbine generator is oneof the main equipments of power plant and a direct producer of electricity, about80percent of our electricity comes from the turbine generator. The development of turbinegenerator plays an important role in the development of power industry. Therefore, weneed to increase the capacity of the generator motor. With the turbine generator capacityincreases, the rotor and the stator coil copper consumption is also increasing. So it willlead to the winding temperature, and even exceed the allowable temperature. Thereliability of its components will be threatened greatly. Thus, the research on thegenerator cooling system is important.In this paper, the rotor and the stator of1000MW ordered hydrogen-cooledgenerator are researched. A length of the semi-axis mode of the rotor, together withstator model and the stator element model, is established. Based on computational fluiddynamics, the three-dimensional numerical simulation study on heat transfer offluid-solid coupling was performed by using finite volume method. The vetilating ductflow structure and flow resistance performance, of the stator of generator, are analyzed.The variations of drag coefficient are obtained. It lays the foundation of further study onthe model and numerical analysis of the rotor ventilation cooling. Resistancecharacteristics and the flow distribution of cooling fluid which flows along the axial andradial wind channel in the rotor are analyzed. Heat transfer characteristics andtemperature field characteristics of the rotor were achieved at the same operatingconditions. Ultimately, it provides a theoretical evidence for guiding the generatordesign and optimization. It is established that: with the speed decreases, the resistancecharacteristic coefficient of the stator unit increases, and almost changes with thequadratic in the velocity. For the single bridge and double bridge of rotor unit, averageheat transfer coefficient of the wind trench of double bridge wall is larger than that ofsingle bridge wall about100W/(m2.K). The temperature of the semi-axis rotorwindings, sub-slot and air-gap increases gradually along the axial direction. The resultsof this study will eventually provide the theoretical basis for the nuclear generators of 1450MW.