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To investigate the sealing mechanism and performance of the symmetric magnetic fluid seal (SMFS) with occlusal pole teeth (OPT), an experimental device was designed. The impact of magnetic fluid volumes and groove widths on the sealing mechanism and performance of the SMFS-OPT was investigated under different environments. Combining experimental results and numerical analyses, the applicability of the magnetic fluid sealing theoretical pressure resistance formula to SMFS-OPT is verified. The results show that low magnetic fluid volume and a large groove width prolong the differential pressure reduction process, thereby reducing the pressure resistance of the sealing device. Increasing the volume of the magnetic fluid increases the sealing device's self-healing rate but does not change the trend of the number of ruptures' impact on the pressure resistance. [ABSTRACT FROM AUTHOR]

To investigate the influence of temperature on the pressure transfer mechanism and failure mechanism for magnetic fluid seal (MFS) with opposite pole teeth (OPT), a sealing device with water circulation channel was designed. Sealing mechanism and performance of the sealing device at different temperatures were experimentally investigated under gas and vacuum environments, respectively, and comparison with the experimental results at normal temperature. Theoretical pressure resistance was calculated according to the theoretical pressure resistance formula for MFS with temperature coefficient. The results show that temperature affects the trend of pressure difference variation for the MFS-OPT. As temperature decreases, self-stability of the magnetic fluid film improves, while pressure resistance and self-healing capability of the MFS-OPT become more pronounced. [ABSTRACT FROM AUTHOR]

To enhance the sealing pressure of normal ferrofluid seals with single magnetic source and small sealing clearance, a symmetrical ferrofluid seal (SFFS) was designed. The study utilizes a combination of finite element simulation and experiments to investigate the influence of crucial factors, including sealing clearance, number of pole teeth, step height, and pole teeth position, on the sealing pressure of SFFS. The findings indicate that the experimental sealing pressure values for SFFS closely match the theoretical sealing pressure values. The sealing pressure of the SFFS decreases as the sealing clearances and step height increase. It increases with an increase in the number of pole teeth. • A symmetrical ferrofluid seal with single magnetic source and small sealing clearance is designed. • Determine the maximum sealing pressure when the pole teeth are on the outer circular surface of the shaft and the end face of the pole piece. • This provides an important reference for the design and application of ferrofluid seal. [ABSTRACT FROM AUTHOR]

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]