Numerical Simulation Research Of Flow Field And Temperature Field Of Salient Pole Synchronous Motor

Brushless salient pole synchronous motor has a wide range of applications in the industrial production,because brushless excitation synchronous motor has the advantages of reliability,stability.Currently,the key technologies encountered in large-scale process of all kinds of salient pole synchronous motors are cooling problems under the complex structure.The cooling air flow is critical in the the motor development,it will affect the safe operation of the motor when the amount of ventilation is small;it will affect the motor efficiency when the amount is large.Our large-capacity salient pole synchronous motors depend on foreign imports because of the limitations of the technique and technological level.The object of this study is 27MW brushless salient pole synchronous motor which is our current single larger capacity,and motor internal flow field and the temperature field of the rotor is researched.Firstly,a three-dimensional physical model is created,then 1/8 three-dimensional machine internal turbulent flow field is calculated numerically adopting computational fluid dynamics method(CFD)when the inlet and outlet pressure conditions are given by manufacturers,the rotor speed is 1500r/min under rated conditions,three-dimensional velocity and static pressure distribution characteristics is researched in rotor.Relative error of its results is 0.5%comparing with another manufacturer,indicating accuracy of the data.Secondly,taking into account the traditional equivalent air duct law can not meet the demand of forecasting peak temperature,three-dimensional flow and heat transfer of the model are calculated coupled to predict the temperature field in the motor under the heat source given by manufacturers,the final structure is obtained whose temperature rise does not exceed the highest temperature.The highest temperature is 127.2? which is located in the center symmetry plane of the copper winding,and the highest temperature of its adjacent insulation is 125.7?,the motor is safely operated without over-temperature.Finally,physical property parameters,geometric structure and the boundary conditions are studied which would influence the flow field and temperature field.Numerical experimental results show that it is necessary to add boundary conditions when flow field in motor is studied.It has little effect on flow field in motor when the distance between inlet and rotor surface varies from 320mm to 485mm.The major factor deciding flow rate in the inner wind path is the position of outlet,not the area.The research method and conclusions mentioned in the dissertation will provide theoretical reference and technical support for ventilation and cooling design of large salient pole synchronous motor.