Advanced sealing technology in mechanical systems with magnetorheological fluid for large gap applications

Sealing technology is critical for the reliability and efficiency of mechanical systems, especially in rotating shaft applications. Traditional ferrofluid (FF) seals, while effective in narrow gaps (0.1–0.3 mm), face significant limitations in maintaining effective sealing under large gap conditions (more than 0.3 mm). To address this challenge, a magnetorheological fluid (MRF) seal optimized for high-speed dynamic applications was proposed. Firstly, a sealing structure was designed, and the rheological properties of MRF were characterized. Then, theoretical models for both FF and MRF seals were derived to analyze their operating principles and performance differences. A custom test bench was constructed to evaluate static sealing performance at 0.1 mm and 0.4 mm gaps and dynamic sealing performance at shear velocities of 0.2, 0.4, 0.6, 0.8, and 1.0 m/s. Experimental results demonstrated that MRF seals achieve higher pressure differentials compared to FF seals, particularly in large gap scenarios. These findings suggest that MRF seals offer a promising alternative for advanced sealing applications in mechanical systems.