Study on Formation and Stability of Virtual Channel Levitated by Strong Magnetic Field

在高纯度材料和化学活性材料的加工中，物体的悬浮和定位而不与壁接触是最理想的。众所周知，抗磁性材料可以被强磁场悬浮起来，通过将两个无限长的北极面对面放置，产生一个中心最弱，径向逐渐变强的非均匀磁场。当磁场足够强时，非磁性流体可以稳定地停留在磁场中心线附近，就像在一个虚拟的管道中一样，并作为一个长的液柱悬浮，甚至可能在管道内流动。为了在空气或真空中制造磁性管道，需要很强的磁铁，这使得实验研究非常昂贵和困难。在磁性流体作为周围流体的帮助下，悬浮的非磁性液体的重力可以与浮力和磁力平衡。这使得即使在弱磁场中也可以稳定地悬浮非磁性液体，这便宜得多并且容易获得。本研究利用这一原理产生液柱和虚拟通道，由于磁管是虚拟管，不是由固体壁形成，而是由磁场形成，悬浮液柱可以变形或偏离平衡位置，研究了悬浮抗磁性液柱在磁场激励扰动下的稳定性，采用倾斜磁体产生发散虚拟通道，采用弯曲磁体产生弯曲虚拟通道。水可以在它们里面顺利地流动。

In the processing of the highly pure material and chemically active material, the levitation and the positioning of objects without contact to the wall is most desirable. It is known that the diamagnetic material can be levitated by the strong magnetic field.By placing two infinitely long north poles face to face each other, a non-uniform magnetic field, which is the weakest at the center and is gradually stronger in the radial direction, is produced. When the magnetic field is strong enough, the non-magnetic fluid can stay at a place around the center line of the magnetic field stably just as if it is in a virtual pipe, and is levitated as a long liquid column or may even flow inside the pipe.In order to produce the magnetic pipe in the air or in the vacuum, the very strong magnet is needed, which makes the experimental study very expensive and hard. With the help of the magnetic fluid as a surrounding fluid, the gravity of the levitated non-magnetic liquid can be balanced with the buoyancy and the magnetic force. This makes it possible to levitate stably the non-magnetic liquid even in the weak magnetic field, which is much less expensive and easier to be obtained. In the present research this principle was used to produce the liquid column and the virtual channel.As the magnetic pipe is the virtual one, formed not by the solid wall but by the magnetic field, the levitated liquid column can be deformed or displaced from the equilibrium position, and the waves can occur along the liquid column.The stability of the levitated diamagnetic fluid column against the disturbance exited magnetically was investigated.The divergent virtual channel was produced with the inclined magnets, and the curved virtual channel with the curved magnets. The water could be made to flow successfully inside of them.