Leakage Rate Control of Magnetic Powder Seals by Lubricant Coatings on Magnetic Nanoparticles and Flow Field Simulation

Magnetic fluid seals (MFSs) have been a popular sealing method, with unique advantages compared to traditional mechanical seals, such as zero leakage, long lifetime, and low resistance torque. However, restricted by the properties of carrier fluids, MFSs cannot work under extremely high or low temperatures. To ensure stability, the pressure capability per stage is also limited. Recently, a novel sealing method using nano-micro magnetic powders has been presented to solve the problems, and leakage rates turn out to be a main focus. Here, we realize the leakage rate control by lubricant coatings on magnetic nanoparticles. Fe
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O
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nanoparticles coated with solid lubricants are prepared by the high-energy ball milling method. Effects of different types of lubricants and ball milling parameters on the leakage rate are studied by magnetic powder sealing experiments. Permeability of magnetic powders is estimated from the experimental data. Furthermore, the flow field distribution of a real magnetic powder seal (MPS) is simulated.