Analysis Of Complex Fluid Field And Ventilation Structure Optimization Of 350MW Air-cooling Turbo-generator

The development of 350 MW air-cooled turbo-generator with complete independent intellectual property rights is of great significance for improving the research and development capacity,design and manufacturing level of large-capacity air-cooled turbo-generator in China and accelerating the pace of catching up with the world-class.However,in order to break through the capacity limit of the generator,there are still some problems to be solved in its research and development,design,manufacturing and other aspects.One of the important methods to improve the ventilation and cooling capacity of 350 MW air-cooled turbo-generator is to improve the distribution and flow characteristics of cooling gas in the machine by optimizing the cooling structure of the generator under a very limited structure size.This paper focuses on the analysis of complex flow field and optimization of ventilation structure in 350 MW air-cooled turbo-generator.Firstly,a 350 MW air-cooled turbo-generator is taken as an example in this paper,and the distribution characteristics of cooling medium in the generator are analyzed in detail Through reasonable simplification,the solution domain of fluid in generator stator and rotor is obtained,and the appropriate element type and mesh number are determined.According to the characteristics of the fluid in the generator,the control equation of the fluid field is obtained,and the appropriate numerical calculation method is selected.Then,the stator and rotor flow fields of generator are studied in this paper.The distribution of air volume in the key ventilation paths,such as the stator ventilation channels and rotor sub-slots,and the pressure distribution in the key ventilation paths,such as the stator ventilation channels and rotor sub-slots,were obtained.Finally,aiming at the difficult problem of rotor cooling,the flow rate and fluid track of stator,rotor and end region are studied when the small fan and windshield plate are adopted respectively.The differences between the optimal structure and the original structure are quantitatively analyzed,and the rational cooling structure is determined.