Research On Ventilation System Of 40MW Salient Pole Synchronous Motor

The development of the electric power industry is based on motor manufacturing.The urgent needs for social development on useful work promote the increase of motor’s unit capacity,meanwhile electromagnetic and thermal load also increased,which directly affect the safe operation and service life of motor.At present temperature rise limit has become a bottleneck restricting the development of motor.In order to achieve a design level of high quality and guarantee the stability and economy of motor operation,efficient and accurate calculation method must be adopted to simulate the flow state of cooling medium,which will provide strong bases for the design of ventilation system.CFD numerical methods adopting in this article based on the finite volume method can simulate the air flow state accurately and forecast temperature rise of each component,which will provide digital and compact design basis for engineers and has vital significance to the development of motor manufacturing industry.In this paper,a 40MW salient pole synchronous motor which has the largest capacity in domestic currently is taken as an example,its whole flow field and temperature distribution law of each rotor component are researched.Firstly,two kinds of layout scheme of support block are proposed based on previous research findings.The physical models of 1/8 main engine with two kinds of rotor structure are established respectively,three dimensional flow field and rotor temperature field are calculated according to the CFD principle under the same rated condition.Air flow distribution,velocity field and temperature field of two kinds of structure are contrastively analyzed and the structure which has better cooling effect is ascertained.The calculation results are compared with results calculated by other software and correctness of the method is verified.Secondly,the fan and air zone in front of the fan are added on the basis of the main engine with better ventilation structure,the computational domain is expanded and closer to the practical engineering.The results are analyzed when the air pressurized by fan automatically and compared with the model without fan.The influence of the fan,s rotating flow field on main engine’s flow field is researched.Finally,the influence of ventilation structure change,such as relative position of support block and there is air under support block or not,thermal properties of materials and periodic boundary setting on numerical results are researched on the basis of the structure with better cooling effect.The results show that two coaxial series rotating flow field influence each other when calculating main engine and associated fan at the same time,air velocity increase,the peak temperature of rotor reduces.The condition setting of numerical calculation is very important and slight negligence may lead to incorrect results.The research method and conclusions in this article will provide reference and guidance for the numerical simulation of motor and ventilation system design of large salient pole motor.