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Preventing the accretion of droplets on surfaces is vital and slippery liquid‐infused porous surfaces (SLIPS) have promising application prospects, such as surface self‐cleaning and droplet transportation. In this work, controllable self‐transport of bouncing droplets on ultraslippery surfaces with wedge‐shaped grooves is reported. The impact behaviors of droplets on SLIPS under various impact velocities and diameters are explored, which can be classified as hover, total bounce, partial bounce, Worthington jet, and crush. SLIPS with wedge‐shaped grooves were designed to transport accreted droplets. An energy and transport model is established to explain the impact and self‐transport mechanism, where the Laplace pressure and moving resistance between droplets play a key role. Finally, SLIPS with branched wedge‐shaped grooves were designed for droplet self‐transport and demonstrated advantages. This work provides a general reference for spontaneous motion control of sessile droplets, droplets with initial impacting velocity, or even liquid films. [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 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]