Research On Fluid-Solid-Thermal Coupling Thermal Field Characteristics Of Magnetic Levitation Spindle

Complex curved surface parts are widely used in aviation,rail transit,automobile industry,chemical energy,powder metallurgy and medical and health fields,etc.The requirement of processing quality and efficiency is increasing day by day,which makes the milling composite processing technology face new challenges.The electric spindle which provides direct power for milling is particularly critical as the core component of the tool holder of the complex B-axis for turning and milling.The magnetic levitation electric spindle has attracted much attention due to its non-mechanical wear,high speed,no need for lubrication,and good mechanical performance.Based on its fluid-solid thermal coupling characteristics,this article starts to study the influence of its internal main heat source and coupled heat transfer on the temperature field,aiming to effectively reduce the internal temperature and thermal deformation of the maglev spindle.The main research contents include:(1)This article embarks from the composition and working principle of the magnetic suspension structure of motorized spindle,through mechanics analysis introduced a mathematical model of five degrees of freedom rotor system,reveals the electromagnetic bearing before and after the failure of bearing principle,based on the Lagrange equation of rigid disk unit and elastic axis section of dynamics modeling,it is concluded that flexible rotor integral dynamics equation,the angular displacement of rigid rotor and parameters such as electromagnetic field component.(2)By analyzing the heating source,basic loss and heat transfer of the rotating subsystem,it can be known that there are two main heat sources in the magnetic suspended rotor system.One is the heating of the rotor winding coil,and the other is the stator loss.By establishing the system thermodynamic model and heat transfer function,the temperature expression between the axial top and bottom of the rotor system is derived.The analysis of the main factors affecting the temperature rise of the rotor system shows that: the current and speed are important parameters for the use characteristics of motorized spindle,but also the main factors affecting the temperature change of motorized spindle,laying a theoretical foundation for further research.(3)Based on ANSYS software,the setting parameters of boundary conditions were calculated.The 3d model was simplified,and the pre-grid and post-grid processing was carried out.The steady-state temperature field distribution of the rotor system under different current and rotation speeds was mainly studied.(4)This article builds a temperature measuring experiment platform to further study the effect of current and speed on the temperature field distribution of magnetic suspension rotor system.By comparing and analyzing the simulation and experimental data,the results show that the coil current and spindle speed are related to the temperature rise of the magnetic suspension rotor system,and they are in direct proportion.The highest temperature of the rotor system occurs at the winding coil of the electromagnetic bearing,and the lowest temperature is distributed at the shaft end.The data obtained from the simulation is basically consistent with the data measured in the experiment,which verifies the accuracy of the thermodynamic model and boundary conditions.Under the conditions set in this article,water cooling has a slightly better cooling effect than air cooling.In this article,the finite element simulation and experimental study provide important basis for the structure design and temperature rise control of the maglev motorized spindle.