Design On Heat Dissipation Structure Of Planar Motor Based On Jet Combined With Bionic Fractal Channel

As the main motor type used in the double working platform of the lithography machine,the positioning and motion accuracy of the planar motor largely determines the machining accuracy of the lithography machine.The temperature increment of the motor caused by the heat loss of the winding array when the planar motor is working is the cause of the decrease of the positioning accuracy of the planar motor.With the development of the planar motor to higher speed,greater acceleration,and higher positioning accuracy,the temperature rise can become more severe and the problems more serious.Therefore,this thesis proposes a jet combined with bionic fractal channel radiator for the problem of temperature rise and uneven temperature distribution of the planar motor.Firstly,the heat loss analysis of the concentric winding magnetic levitation permanent magnet synchronous planar motor(SPMPM)is carried out,and the average heat loss value of each phase coil winding of the concentric SPMPM under two working conditions is obtained.The thermal simulation software is used to simulate the SPMPM without heat dissipation device under two working conditions,and the temperature distribution of the motor surface is obtained.The common high-temperature zone under two working conditions is determined to be the central winding E of the coil winding array.Then,the heat transfer characteristics of single-hole jet and array jet are studied by Fluent simulation software.The effects of jet Reynolds number,jet aperture and jet impact height on the heat transfer characteristics of single-hole jet and the effects of jet Reynolds number,jet hole spacing and jet impact height on the heat transfer characteristics of array jet are discussed respectively.Then,a comprehensive rating coefficient was defined to evaluate the comprehensive performance of flow and heat transfer in bionic fractal channels.The effects of initial channel length,initial channel width,channel thickness,channel length ratio and fractal angle on the flow and heat transfer performance of bionic fractal channels were studied by Fluent.Then,according to the analysis results of the influence of the above parameters on the flow and heat transfer characteristics of the array jet and the bionic fractal channel,the structural parameters of the designed jet combined with the bionic fractal channel radiator are determined,and the flow and heat transfer are simulated and analyzed.Under the same boundary conditions,the designed radiator is compared with the traditional parallel channel radiator and the jet coupled parallel channel radiator with the same channel volume fraction.The results show that the flow and heat transfer characteristics of the jet combined with the bionic fractal channel radiator designed in this thesis are better than those of the traditional parallel channel radiator and the jet coupled parallel channel radiator.Compared with the traditional parallel channel radiator,the average temperature rise is reduced by 28.03%,and the inlet and outlet pressure drop is reduced by 75.74%.Compared with the jet coupled parallel channel radiator,the average temperature rise is reduced by 41.24%,and the inlet and outlet pressure drop is reduced by 72.1%.Therefore,the superiority of the flow and heat transfer performance of the designed jet combined with the bionic fractal channel radiator is proved.Finally,a liquidcooled heat dissipation experimental measurement system was built,and the designed jet combined with bionic fractal channel radiator was experimentally measured at different inlet flow rates.The experimental results were obtained and compared with the simulation results.The results show that the simulation results of the outlet fluid temperature and the maximum temperature of the top surface of the radiator are not more than 6% of the experimental results,which verifies the accuracy of the simulation results and illustrates the effectiveness and feasibility of the design results.