屈服应力对磁性液体密封性能的影响

磁性液体密封是磁性液体最成熟的应用。在应用中发现，随着时间的推移，静止放置的磁性液体密封的耐压都将升高；如果是旋转密封，启动扭矩将增大。实验测定了磁性液体密封的启动扭矩和密封耐压随静置时间的增大关系，分析了引起这一现象的原因，修正了磁性液体密封的耐压和扭矩公式。结果表明，磁性液体的屈服应力大小是影响磁性液体的密封耐压和启动扭矩增大的主要因素，屈服应力越大，磁性液体密封的耐压和启动扭矩越大。研究结果为减小磁性液体密封的启动扭矩提高磁性液体密封的耐压性能提供了实验和理论参考。

The Influence of Magnetic Fluid Yield Stress on the Performance of Magnetic Fluid Seal

Magnetic fluid seal is one of the most mature applications of magnetic fluid. It is found that the anti-pressure capacity of the static or dynamic magnetic fluid seal may rise over time. If it is a dynamic seal, the starting torque will increase. These phenomena are investigated through experiment. Then the concept of yield stress of magnetic fluid is introduced to explain qualitatively the phenomena. And the formulas of anti-pressure capacity and torque are improved. The results show that the yield stress of magnetic fluid is the main factor inducing the increase in the anti-pressure capacity and torque of magnetic fluid seal. The greater the yield stress is, the higher the anti-pressure capacity is, and the larger the starting torque is. The results provide a design basis to reduce the starting torque and improve the anti-pressure capacity of magnetic fluid seal.