Numerical Calculation And Analysis Of The Flow Field For Large Turbo-generator With Different Rotor Structure

With the rapid development of the economy in our country,the demand for electric power is increasing.Thermal power generation occupies a large proportion in Chinese electric power production,and the turbine generator is an indispensable equipment for thermal power generation.Due to the simple structure,low maintenance cost and good safety,air-cooled turbo-generator is widely used in thermal power generation.The larger the single-motor capacity of the air-cooled turbine generator is,the better its economy.However,with the increase of the turbine generator capacity,the problem of motor cooling becomes very prominent.Therefore,it is very important to design the ventilation cooling system of air-cooled turbo-generator reasonably.For large turbo-generators,ventilation and heat dissipation of rotor part have been the focus of the research on temperature rise.In this paper,a 350 MW air-cooled steam turbine generator is taken as the research object,and the three-dimensional fluid field in steady-state operation of the motor is calculated and analyzed by finite volume method.The 1/4 model of the motor is established,and the total ventilation volume in the original structure of the motor is calculated.The static pressure distribution in the motor stator and rotor ventilation ducts,the fluid distribution in the motor stator and rotor air duct,the average velocity of the fluid in the radial ventilation duct of the motor rotor and the heat dissipation coefficient of the motor rotor air duct are analyzed.The different structures of the rotor end of the motor are calculated by the same method.Two rotor end structure schemes are proposed.Scheme 1: the windshield between the rotor end windings is removed.Scheme 2: a rotor small fan is added under the rotor end guard ring.Under different schemes,the total ventilation volume,the distribution of fluid volume and velocity of cooling air in radial ventilation duct of rotor and the factor of heat dissipation are analyzed.The three structural schemes are compared and analyzed,and the beneficial conclusions are obtained.