高转速磁性液体密封结构的优化设计

Optimization Design of Structure of High-speed Magnetic Fluid Seals

普通磁性液体密封装置应用于高转速轴密封时,因离心作用的影响会引起磁性液体出现大量迁移,导致密封性能变差,高转速过程中产生的大量摩擦热引起磁性液体温度升高,导致磁性液体黏度降低、密封性能受损。设计一种适用于高转速的磁性液体密封结构,在普通磁性液体密封结构的基础上通过互换旋转磁极与静止磁极位置,消除离心力对磁性液体的影响;通过增加非导磁套筒,加快热量传递,降低磁性液体温度。对密封结构关键部件的几何参数进行优化,确定磁极和永磁体的径向尺寸、永磁体的轴向长度,优化后密封间隙处磁通密度分布更均匀,磁通密度梯度更大,密封性能最优。通过ANSYS分析,模拟出高转速磁性液体密封结构中磁通密度的分布和极齿上的磁通密度大小,证实密封结构优化的合理性。

When the general magnetic liquid sealing device is used for the high-speed rotating shaft seal, due to the influence of centrifugal force, a large number of magnetic fluids are transferred, resulting in deterioration of sealing performance.Meanwhile, in the process of high-speed rotating, the increase netic fluid because of a large amount of heat generated by friction of temperature and the decrease of viscosity of the magdamage the sealing performance of magnetic liquid. A new high-speed magnetic fluid sealing structure was designed,which eliminated the effect of centrifugal force on the magnetic fluid by changing the mutual position of rotating and static sealing magnetic poles of the general magnetic liquid seal- ing device,decreased the temperature of magnetic fluid by adding a nonferrous sleeve to accelerate heat transfer.The geo- metric parameters of the key parts of the seal were optimized, and the radial size of magnetic pole and permanent magnet and the axial length of the permanent magnet were determined.After optimization, the seal structure has more uniform mag- netic flux density distribution in the sealing gap, larger magnetic flux density gradient, and better sealing performance. By using ANSYS, the distribution of magnetic flux density of the high-speed magnetic fluid sealing structure and the pole tooth was simulated.The simulation result validates the rationality of sealing structure optimization.