磁流体黏度可随外部磁场强度发生变化,故可将其作为非接触式机械密封端面的润滑介质,通过改变外部磁场强度来实现磁流体膜动压性能的控制。为提高磁流体动压机械密封的密封性能,设计一种磁场发生器,该磁场发生器可通过改变电流来调节磁流体膜的黏度,从而产生不同的动压,实现对流体膜动压效应的控制。采用数值分析的方法,对由动环、静环、磁流体膜及磁场发生器组成的导磁结构的磁场进行分析,获得导磁结构中磁力线、磁场强度、磁感应强度分布规律。研究发现,导磁结构中的磁力线几乎全部穿过密封环端面,该处的磁场强度达到最高水平;磁力线在垂直于密封端面方向上有一定的磁场梯度,且磁流体膜中的磁场强度与磁场发生器的电流强度成正比。
Magnetic liquid can be used as a lubrication medium of non-contact mechanical seal face for its viscosity can be changed by the external magnetic field intensity, the hydrodynamic performance of magnetic liquid membrane can be controlled by changing the external magnetic field intensity.In order to improve seal performance of magnetic liquid hydrodynamic mechanical seal, the magnetic field generator was designed, which can produce different dynamic pressure by changing the current to adjust the viscosity of liquid membrane, and realize dynamic pressure effect control of fluid membrane.Through numerical analysis method ,the magnetic field was analyzed of magnetic transmitting structure which consisted of moving ring and static ring, liquid membrane and magnetic field generator, and the magnetic force lines, magnetic field intensity and magnetic induction intensity distribution laws of magnetic transmitting structure were obtained.The results show that almost all magnetic force lines in the magnetic structure pass through the seal face, and the magnetic field intensity in sealing gap reaches the highest level.The magnetic force lines in the direction of perpendicular to the seal face have a certain magnetic field gradient, and liquid membrane in the magnetic field intensity is proportional to the current strength of the magnetic field generator.