Calculation And Analysis Of Temperature Field In Non-salient Pole Synchronous Generator

The research of physical fields inside large generator is a synthesis problem which refers to multi-disciplines and multi-specialties. There are some difficulties and engineering significances to calculate physical fields in generator accurately because of complex stator structure, rotation of rotor and multi-coupled of physical fields, which has become one of the most difficult problems of international electrical machine field.In this dissertation, some documents about electromagnetic field, fluid field, temperature field are researched, the development of this issue is discussed and the shortcomings of research are given. The purposes, significance and contents of research for problem are confirmed.The influence of fluid flow inside stator radial ventilation duct of large generator on stator temperature is analyzed using numerical method, the fluid speed inside ventilation duct was calculated using finite volume method (FVM),and the specific distribution of fluid flow was got. Based on that, the heat transfer coefficients of the surfaces were solved and numerical relationship of multi-fields couple inside generator stator complex structure was ascertained.Based on the basic principles of fluid field and temperature field, internal heat transfer characteristics of the large generator stator with corrugated board is analysis. After that, the influences of different corrugated plate on stator temperature field are got. In addition, as harmonic magnetic field move at different speeds relative rotor and stator created by harmonic magnetic potential the stator and rotor windings in the air gap, the additional losses were created in the iron core. It is general difficult to calculate the additional losses accurately and determine the distribution accurately, in this article, the influence of the penetration depth of different harmonic on stator temperature field was researched. Based on the Fourier heat conduction law and Newton's law of heat release, a new method to determine heat transfer coefficient on stator windings main insulation out surface was developed, in which the anti-iterative numerical method was used and the data about cooling medium in ventilation groove do not have to be known. Using this method, the temperature field throughout the domain can be determined .It also provides a new way based on the theory of fluid similarity.The corresponding research can be made more detailed and deeply by the investigation, which not only improves the calculation precision of large generator physical fields but also improves the ventilation effect of large generator at the same time, reduce the accident rate, elevate the working performance and improve the operating reliability and security of large generator.