| Cylindrical permanent magnet governor has many advantages,such as soft start and overload protection,low requirement for centering installation,low vibration and noise,long service life,wide range of speed regulation and significant energy saving effect.However,the main components of the cylindrical permanent magnet governor have a serious fever under some operating conditions,which affects the normal operation of the permanent magnet governor.Therefore,it is very important to study the temperature field distribution and heat dissipation of the cylindrical permanent magnet governor during its operation.Firstly,the basic theory of electromagnetic field is analyzed and deduced.Based on these theories,two-dimensional and three-dimensional finite element simulation analysis of magnetic and eddy current field of cylindrical permanent magnet governor is carried out by using Maxwell 2D and Maxwell 3D modules in ANSYS Workbench17.1 software.The distribution of magnetic induction line and magnetic induction intensity in cylindrical permanent magnet governor and the distribution of eddy current in copper ring are studied by post-processing results.The heat generated by eddy current in copper ring is used as the direct heat source for temperature field analysis of cylindrical permanent magnet governor.The variation of output torque,output power and eddy current loss power with meshing area and slip ratio is analyzed.The two-dimensional and three-dimensional simulation results of magnetic and eddy current fields are compared.Based on the analysis of the basic theory of engineering heat transfer,the steady-state and transient temperature fields of cylindrical permanent magnet governor are simulated by using Maxwell 3D,Steady-state Thermal and Transient Thermal modules in ANSYS Workbench 17.1 software.Through the simulation results of transient temperature field,the heating process of the components in cylindrical permanent magnet governor is studied.Based on the simulation results of steady-state temperature field,the temperature distribution of the components in cylindrical permanent magnet governor is studied when the temperature reaches a steady state.The variation of maximum temperature of copper ring and permanent magnet block with meshing area and speed difference is analyzed.Finally,the simulation results of transient and steady-state temperature fields are compared.In order to verify the accuracy of finite element simulation results of magneticfield and temperature field of cylindrical permanent magnet governor,a output torque measurement system of cylindrical permanent magnet governor and a temperature measurement system of copper ring and permanent magnet block were designed.The composition and construction of the experimental system are introduced and the measurement process is analyzed in detail.After the experiment,the measured values of the output torque and the maximum temperature of copper ring and permanent magnet block under different operating conditions are compared with the results of finite element simulation,which verifies the accuracy of the finite element method to study the magnetic field and temperature field of the cylindrical permanent magnet governor.Finally,based on the analysis of magneto-thermal coupling of cylindrical permanent magnet governor,Maxwell 3D,Steady-state Thermal and Response Surface Optimization modules in ANSYS Workbench 17.1 software are used to optimize the structure of two kinds of fins of cylindrical permanent magnet governor:straight rib and circular rib.After optimization,the maximum temperature of copper ring and permanent magnet block is 26.5% and 20.9% lower than before by using the straight fin to dissipate heat.The maximum temperature of copper ring and permanent magnet block is 43% and 33.9% lower than that before by using the arc fin to dissipate heat. |
PDF Full Text Request