一种添加挡板的磁流体液体动密封结构

磁流体密封具有低磨损、零泄漏、高寿命等优点, 已经被广泛地应用于气体密封中。然而, 当用磁流体旋转密封液体时, 被密封液体与磁流体在运动过程中存在复杂的物理过程, 导致磁流体密封性能较差。本文理论分析了磁流体与被密封液体速度差引起的液-液界面不稳定性, 设计了添加挡板的磁流体密封结构。实验表明, 添加挡板可明显提高磁流体密封液体的性能。当密封间隙0.05 mm、转轴转速2000 r/min时, 选取挡板厚度10 mm, 磁流体密封可连续工作120 h不泄漏。

Novel Shield between Magnetic Fluid and Sealed Liquid: A Theoretical and Experimental Study

A novel type of shield, comprising the upper/lower cylindrical rings with identical height and outer diameter but with different inner diameters, was developed to improve the stability at the interface of magnetic fluid and sealed liquid medium.The influence of the ring height, shaft's rotating speed and sealing gap, on the complete sealing time was theoretically analyzed in Kelvin-Helmholtz instability theory and experimentally investigated with the lab-built test platform.The experimental results show that the new shield significantly increased the zero leakage sealing time.To be specific, under the optimized conditions, including a ring height of 10 mm, a sealing gap of 0.05 mm and a rotation speed of 2000 r/min, the magnetic fluid seal with the new shielding rings displayed zero leakage after continuous operation for 120 h.