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To investigate the failure mechanism of the magnetic fluid seal (MFS) with opposite pole teeth (OPT) in gas and vacuum environments, a sealing device was designed to directly observe the surface shape of the magnetic fluid film. The failure mechanism and sealing performance of the MFS-OPT in different environments were investigated and discussed with the ordinary MFS. Numerical analysis was conducted to study the magnetic field distribution of the sealing device. The self-healing ability of the MFS-OPT in different environments was investigated. The results indicate that the pressure transfer process of sealing device occurs in a step-by-step manner. When the sealing device fails, it will go through two consecutive stages of microleakage and complete leakage. On the other hand, when the ordinary MFS fails, it first goes through a bubble stage. The magnetic fluid in the sealing device leaks from the middle location of the opposing pole teeth. The sealing device exhibits higher pressure resistance in a gas environment than that in a vacuum environment. Both gas and vacuum environments have a higher pressure resistance for MFS-OPT compared to ordinary MFSs. • The MFS-OPT device can visualize the change of MF film shape. • In the MFS-OPT, the leakage channel occurs in the middle of the opposing PT. • In a gas environment, the gas bubbles are not produced by MF film during failure. • Pressure resistance and self-healing ability of the MFS-OPT are superior to the ordinary MFS. [ABSTRACT FROM AUTHOR]

Magnetic fluid seal (MFS) has been widely applied in the vacuum environment, but its pressure transfer mechanism has been less studied. This paper investigates the pressure transfer mechanism of MFS in the vacuum environment by designing an experimental device of MFS mechanism, which can observe the change of liquid film during the pressure transfer. Meanwhile, the pressure transfer mechanism of the designed device in the vacuum environment is compared with the that of MFS in the gas environment. The self-repairing performance of MFS in both vacuum and gas environments is investigated. Based on the MFS theory, the magnetic field distribution of the experimental device is analyzed numerically, and the theoretical pressure resistance is calculated and compared with the experimental value. The results show that the pressure transfer mechanism of MFS in the vacuum environment is similar to that in the gas environment with different forms. The pressure transfer form in the vacuum environment is magnetic fluid liquid film to produce a leakage channel. It is concluded that the self-repairing performance of MFS in the vacuum environment is better than that in the gas environment. • Using a comparative study approach. • The pressure transfer mechanism of MFS in the vacuum environment is similar to that in the gas environment. • The pressure transfer of MFS in the vacuum environment is the form of leakage channels generated in magnetic fluid film. • The self-repairing performance of MFS in the vacuum environment is better than that in the gas environment. [ABSTRACT FROM AUTHOR]