Simulation Of Thermal And Flow Fields For 20MW Non-salient Pole Motor With Inlets Of Rotor Wind Path Locally Blocked

During the process of the development and research of the motors, temperature rise has become a limiting factor. With the electromagnetic and thermal loads increasing in motor, it is critically important to simulate the flow state of the coolant and temperature distribution of the motor reasonably and accurately and computational fluid dynamics receives more and more attention because it can meet the above requirements. In this paper, the flow state of the coolant and temperature rise of different components of the motor are analyzed based on finite volume method and this can provide reliable and efficient data for the motor development engineers.In this paper, a 20 MW non-salient pole synchronous motor with inlets of rotor wind path locally blocked is taken as an example and its whole flow field and temperature distribution law of multiple rotor slots are simulated under the fault condition. Firstly, the physical model of the flow field is established, then three-dimensional turbulence equations inside the 1/8 whole motor are numerically simulated under the rated condition. The distribution laws of air flow rate, velocity field and pressure field of the motor are analyzed and the influence of the blockage fault on flow field is obtained. The error between numerical results and experimental data meets the requirements which can verify the accuracy of the calculation method.Secondly, under the premise of the physical model of the flow field, the solids components of each slot of this computational domain are established including windings, insulation, spacing trips, retaining ring and so on. Then the heat sources are given and the temperature field of rotor slots is simulated and calculated with the local blockage fault of wind path. The temperature distribution laws of the rotor end segment and rotor body segment are obtained and the influence of the rotational direction on temperature field is also researched. The temperature values of the longest slot are compared with that of the manufacturer obtained by other methods.Finally, the influent factors on CFD numerical simulation results of nonsalient pole motor are analyzed. The factors include the changes of the wind path, the blockage of the three-dimensional model and the values of the turbulence intensity. Their influences on temperature field of rotor multi-slots are researched. The results show that the air volume flow rate of the rotor slots decreases when the wind path is blocked, so we must try our best to avoid the blockage failure during the development and arrangement of the motors. The research in this paper can provide a theoretical basis and guidance for detecting and improving the local blockage fault of rotor slots of the similar motors.