Modern rotor systems with gas-lubricated bearings typically operate above the first critical speed, requiring low damping for efficiency above resonance and high damping for vibration suppression at critical speed. Traditional hermetic squeeze film dampers (HSFDs) for gas bearings suffer from exhibit frequency-dependent damping degradation at high frequencies. To address this limitation, a squeeze-mode magnetorheological (MR) fluid damper is proposed, enabling real-time dynamic damping adjustment via magnetic field control. Three-dimensional finite element analysis (FEA) characterized magnetic field distributions under varying currents, while a theoretical model incorporating viscous-inertial-MR effects was developed. Multi-parameter excitation experiments validated that coil energization achieves 2.46-fold damping regulation at 120 Hz excitations, increasing damping from 2.95 kN·s/m (de-energized) to 7.26 kN·s/m (energized). Analytically derived expressions established a linear current-frequency relationship for maintaining constant damping across the 20–200 Hz frequency range. The proposed MR damper resolves the conflicting damping demands in high-speed rotor systems, demonstrating superior broadband adaptability compared to conventional HSFDs.
Zhang et al. (Sat,) studied this question.