Calculation And Analysis Of Three Dimensional Flow Field Of Large Air Cooled Turbo-generator

The power industry in our country has made a rapid development,people's lives are more and more inseparable from electricity.With the economic take-off and the concept of environmental protection getting more and more popular,in order to achieve sustainable development,China's power plants are making a crucial step toward large nuclear power plants,large hydropower plants,large coal-fired power plants and large-scale renewable energy bases.Large generators have their own advantages,including but not limited to: reducing spare capacity,rational use of power resources,rational distribution of load,peak load shifting and improve power supply reliability.A key factor limiting the capacity increase of large generators is temperature rise.To this end,people have designed a variety of cooling options,such as air cooling,water cooling,hydrogen cooling,and hybrid cooling such as air-air cooling,air-water cooling.Although the cooling effect of water cooling,hydrogen cooling among these cooling methods are good,the equipments of those methods are complex and operations and maintenances are not convenient.Therefore,air cooling is undoubtedly the most effective way of cooling.To further enhance the cooling effect of air cooling,increase the rated capacity of the generator,is the key to solve these problems.In this paper,a simulation model of 350 MW large-scale air-cooled turbine generator was built for the study object.Take the 1/2 axial domain and 1/2 circumferential domain as the analysis of the study.The finite volume method was used to simulate the fluid characteristics of the air cooling system in the motor.The size and evolution of the characteristic quantities of the flow,velocity and pressure of the stator,the rotor and the end of the motor are mainly sampled and analyzed.The results of the total flow matches the design value,but the flow distribution of the motor tooth plate in the stator end is still somewhat different.The flow distribution of the air duct of the motor tooth plate is much greater than the design value,but the cooling area here is limited,leading part of the cooling wind wasted.In this paper,three amendments are proposed for the motor tooth plate,which are calculated and compared.In addition,three schemes are proposed in the design of the rotor end.In order to analyze the advantages and disadvantages of different schemes at the rotor end,modifications are made in the calculation domain model,and then their respective simulations are analyzed.Through a large number of numerical simulation of the fluid field of the motor,the fluid flow tendency and flow distribution in the motor are basically grasped.The result of the simulation is identical to the design value,which is a proof of the accuracy of the calculation and the feasibility of the ventilation scheme.It provides a reference for the research of the key technology of cooling methods of this type of air-cooled generator.