【作者】 王凯；

【导师】 汪家琼；

【作者基本信息】 江苏大学 ， 动力工程（专业学位）， 2019， 硕士

【摘要】 磁力联轴器作为磁力泵的核心传动部件,以其无接触式力矩传动的方式与静密封结构特点,解决了磁力泵在工作中介质外泄的问题,被广泛运用于各工业行业中。针对目前在磁力传动研究方面的不足,本文在现有高速“湿式”磁力传动试验台基础上,改进设计并加工了一对圆筒型磁力联轴器,以此展开磁力联轴器在磁感应强度分布、磁转矩与磁涡损计算、传动性能影响因素分析以及磁-热流固多场耦合分析这四个方面的研究:（1）借鉴表贴式无刷永磁直流电机对瞬态场下磁场强度的分析思想,基于Maxwell电磁场基本理论、磁场可叠加原理,构建了圆筒型磁力联轴器的数学解析模型,从理论上推导了分别位于磁钢区与气隙区内磁感应强度分布的解析计算式,为圆筒型磁力联轴器磁场强度的分析提供参考。（2）运用不同方法计算模型磁转矩与磁涡损值。由经验式,得出在5000 r/min时的最大磁转矩与磁涡损分别为:_max经验=91.63 N?m、_经验=3.927 kW。运用Maxwell软件对2D与3D模型进行瞬态磁场的分析,得出以下结论:（a）.在一个运动全周期内,磁转矩与间隙间合力随磁转角变化呈正弦型且变化周期一致,分别在11.25°、33.75°处达到峰值;磁涡损与间隙间磁密随磁转角差呈周期变化,在22.5°处达到峰值。在研究参数范围内,发现磁转矩与间隙间合力、磁涡损与间隙间磁密的分布随磁转角差分别以周期值2π/p（p为磁极对数）、4π/p变化而变化。（b）.对比三种方式所得最大磁转矩与磁涡损结果有:_max经验>_max2D>_max3D、_经验>_2D>_3D,这是由磁钢端部漏磁现象所导致。（3）以磁转矩与磁涡损为评判指标,对磁力联轴器传动性能的影响因素进行探究。研究发现:（a）.磁极对数增加对磁转矩与磁涡损同时存在影响,且呈现先增加后减小而后趋于平稳的趋势。为方便磁极对数选择,本文引入磁钢材料利用率概念,对模型进行参数优化计算,得出本模型在16对时磁转矩与磁涡损达到最佳值。（b）.转速主要影响磁涡损,随转速的变化磁涡损表现9)9)²₄4))/9)9)²₄4)+1)的关系;转速对磁转矩的影响非常小,转速每增加1000r/min,磁转矩约减小0.5%。（c）.工作温度对传动性能的影响主要由改变磁钢磁导率引起。对比20℃时磁钢的传动性能,60℃时磁转矩减小约2%,而在150℃时,磁转矩减小了35%。（d）.磁钢间隙增大会导致磁转矩与磁涡损小幅度减小。但在间隙间加入基体（A3钢）时,同一条件下,会导致磁涡损增加1.2倍左右。（e）.磁钢倾斜角增加会使磁转矩与磁涡损小幅减小。倾角每增加2°,最大磁转矩降低约0.68 N?m,磁涡损减小10W左右。但磁钢倾角增加会使间隙间磁合力的波动幅度更小。对于本模型,磁钢倾角在为6°（π/4p）时间隙间磁力幅度最小。（f）.磁钢分级个数对传动性能的影响主要与磁钢充磁方式有关。当对轴向各级磁钢采用同一充磁方式时,分级个数对磁转矩与磁涡损几乎没有影响。当采用交错充磁方式时,会使磁转矩与磁涡损大幅度减小,且在间隙间会出现随分级个数增多而增多的低磁感应强度区域。（4）基于ANSYS-Workbench耦合平台,分析了转速对试验台冷却循环回路流场的影响,得出:转速变化主要影响隔离套段内的流场。流体经轴孔以一定流速流出后在隔离套底部均匀散开,在最外缘处达到最低值。针对磁热效应对磁转子结构与温度分布的影响分析,得出:（a）.在隔离套上:温升,形变与应变随转速的增大呈线性迅速增长,对比3000r/min时,在10000 r/min下的最大温升、形变以及应力皆增长了10倍左右。其中在温度分布上:高温区域主要集中于与磁钢对应的长度范围内,到圆筒壁两端呈明显分层现象。在结构上:最大形变点与高温集中区域一致,且在周向上均匀向外膨胀,径向上往两端呈梯度递减趋势。对比磁场与流场对隔离套的应力分布影响,得出磁热效应是主导隔离套产生大形变的主要因素。（b）.在磁转子体上:应力与形变随转速的增大呈线性增加,在周向上均匀分布而轴向与径向上梯度递减。其中内磁转子体上,应力主要集中于包封套表面;外转子体上,应力主要集中于与磁钢交接面上;隔离套上,应力主要集中于与对应磁钢的长度范围内且形变值最大。更多还原

【Abstract】 As the core component of magnetic pump,magnetic coupling is widely used in various industries because of its non-contact torque transmission mode and static sealing structure,which solves the problem of medium leakage when magnetic pump works.Because of the deficiencies in the current research of magnetic drive,a pair of cylindrical magnetic coupling is improved and designed which is based on the existing high-speed‘wet’magnetic drive test-bed,and the following four aspects are studied:magnetic field intensity distribution,magnetic torque and magnetic eddy loss calculation,transmission performance influencing factors analysis and magnetic-thermal-fluid-solid multi-field coupling analysis.（1）Based on the theory of Maxwell’s electromagnetic field and the principle of superposition of magnetic field,the mathematical analytical model of cylindrical magnetic coupling is constructed,and the analytical formulas of the intensity distribution in magnetic field of the magnetic steel and air gap regions are deduced theoretically,which can provide reference for the calculation of the intensity in the magnetic field of cylindrical magnetic coupling.（2）According to the empirical formula,the magnetic torque and the magnetic eddy loss of the design model are calculated in different ways.It is concluded that the maximum magnetic torque and the magnetic eddy loss at 5000 r/min are:_maxEx=91.63 N?m、_Ex=3.927 kW.Maxwell software is used to analyze the transient magnetic field of 2D and 3D models,respectively.The conclusion is that:（a）.In a whole period of motion（45°）,the resultant force between magnetic torque and clearance varies sinusoidal with the magnetic rotation angle,and the trend is consistent,reaching the peak at 11.25°and 33.75°,respectively;And the magnetic density between magnetic eddy loss and clearance varies periodically with the difference of magnetic rotation angle,reaching the peak at 22.5°.Within the range of parameters,it is found that the resultant force between magnetic torques and clearances,the distribution of magnetic eddy loss and magnetic density between clearances vary with the variation of magnetic rotation angle with the periodic value of 2π/p（p is the magnetic poles）and 4π/p,respectively.（b）.The results of maximum magnetic torque and eddy loss obtained by three methods are as follows:_maxEx>_max2D>_max3D、_Ex>_2D>_3D.Through comparative analysis,it can be seen that the results of 3D magnetic field calculation are body torque and magnetic eddy loss.The leakage effect at the end of the model is fully considered.Therefore,the 3D numerical simulation method is selected for follow-up research.（3）The influence of the change of magnetic steel structure on the transmission performance of magnetic coupling is studied by using magnetic torque and magnetic eddy loss as evaluation indexes.The results show that:（a）.The increase of magnetic pole logarithm has a simultaneous effect on magnetic torque and magnetic eddy loss,and both of them tend to increase first,then decrease,and finally stabilize.In order to facilitate the selection of magnetic pole logarithm,parameters of the model were optimized by introducing the utilization ratio of magnetic steel material.The model reached the optimum value of magnetic torque and magnetic eddy loss in 16pairs.（b）.Rotational speed mainly affects the magnetic eddy loss,and the relationship between the magnetic eddy loss and rotational speed is9)9)²₄4))/9)9)²₄4)+1).Rotational speed has little effect on the magnetic torque while the magnetic torque decreases by about 0.5%with the increases of rotational speed by 1000 r/min.（c）.The influence of working temperature on transmission performance is mostly caused by changing the permeability of magnetic steel.Compared with the transmission performance of magnet steel at 20℃the magnetic torque decreases by about2%at 60℃and 35%at 150℃.（d）.Increasing the gap between magnets will lead to a small reduction in magnetic torque and eddy loss.However,when matrix（A3 steel）is added between the clearances,the magnetic torque decreases slightly,but the magnetic eddy loss increases by about 1.2 times.（e）.Increasing the inclination angle of the magnet will result in the decrease of the magnetic torque and the magnetic eddy loss slightly.The maximum magnetic torque decreases by 0.68N?m and the magnetic eddy loss decreases by about 10 W when the inclination angle increases by 2°.However,the increase of the inclination angle of the magnet will make the fluctuation of the magnetic force more uniform.For this model,the tilt angle of the magnet is the smallest in the time gap of 6°（π/4p）.（f）.The influence of the number of magnet grades on the transmission performance is mostly related to the magnetizing method chosen by the magnet.When the same magnetizing mode is applied to the axial magnets,the number of stages has no effect on the magnetic torque and the magnetic eddy loss.When the staggered magnetization mode is used,the magnetic torque and eddy loss will be greatly reduced,and the low intensity in magnetic field will appear among the clearances as the number of stages changes.（4）Based on ANSYS Workbench coupling platform,the influence of rotational speed on the flow field in the circulating circuit of the test bed was analyzed.It is concluded that:the change of rotational speed generally affects the flow field in the isolation sleeve.After flowing out of the shaft hole at a certain velocity,the fluid disperses evenly at the bottom of the isolation sleeve and reaches the lowest velocity at the outermost edge.In view of the influence of magnetic-thermal effect on the structure and temperature distribution of the magnetic rotor,it is concluded that:（a）.On the isolation sleeve,the temperature,deformation and strain increase linearly and rapidly with the increase of rotational speed.Compared with the speed of 3000r/min,the maximum temperature,deformation and stress increase about 10 times at the speed of 1000r/min.In terms of temperature distribution,the high temperature region mostly concentrates in the corresponding length range with the magnet steel,while there are obvious stratification phenomena at both ends of the cylinder wall.Structurally,the maximum value of deformation is consistent with the high temperature concentration area,and expands evenly outward in the circumference,and decreases gradually in the radial direction to both ends.By comparing the effect of magnetic field and flow field on the stress of isolation sleeve,it can be seen that the magnetic-thermal effect is the main reason leading to the large deformation of isolation sleeve.（b）.On the magnetic rotor body,the stress and deformation increase exponentially with the increase of rotational speed,and distribute is unified in the circumference while the gradient decreases in the axial and radial direction.On the inner magnetic rotor body,the stress normally concentrates on the envelope surface;on the external rotor body,the stress mostly concentrates on the interface with the magnetic steel;on the isolation sleeve,the stress normally concentrates on the length range of the corresponding magnetic steel.Meanwhile,the deformation is the largest.更多还原