Research On Flow-thermal Coupling Field In The Stator And Rotor Of The Non-salient Pole Synchronous Machine

Calculations of temperature rise of the motor are an important part of the motor design.There are too many factors affecting the motor temperature rise.It is closely related with not only the value of the electromagnetic and heat loads,but also the characteristic of materials,manufacturing processes and design of ventilation cooling system.The calculation of temperature rise involves not only the average temperature rise,but also the motor temperature field.The motor lifetime is also reduced if the temperature rise of local hot spot beyond the temperature rise limit of the insulation structure.Because the application of the air-cooled motor is more and more widely,the analysis of the air-cooled motor is of great significance.For an air cooling non-salient pole synchronous machine,the three-dimensional field of flow-thermal couple in the ventilation system is simulated based on the principle of computational fluid dynamics(CFD).Firstly,establish three-dimensional flow field model of the stator and rotor integration,obtained the flow characteristics of pressure and flow by numerical calculation.Identify that the cooling condition of the longest rotor coil is the worst of the rotor coils.Propose that make the stator in the scope of one tooth and the longest rotor coil as the computational domain when separately simulate the temperature and flow field of the stator and the rotor.Secondly,establish the three-dimensional physical model for the longest coil of rotor,obtain flow and temperature fields by numerical simulation.Analyze the characteristics of temperature distribution and the effect of flow distribution on the temperature rise.Identify that the maximum temperature of the rotor located on the surface of slot wedge when take the pressure inlet as the boundary condition.The overall temperature is reduced when take the mass flow inlet as boundary condition based on the flow data of the integration of stator and rotor,and the maximum temperature located on rotor slot coil.Finally,establish the three-dimensional model of the stator in range of an iron core tooth,obtain the data of flow field and the temperature distribution,and locate the maximum temperature point.On this basis,re-coupled numerical simulation of flow field and temperature field after the reduction of the binding between the ends of the upper winding,and make sure that to reduce the fixed structure of the upper bars can reduce the maximum temperature of the stator bars.The results obtained in this calculation would provide a powerful reference for the design of ventilation system and calculation of temperature rise in the electric motor.