Vibration suppression of counter-rotating dual-rotor systems under aerodynamic excitation with elastic ring magnetorheological dampers

The counter-rotating dual-rotor architecture, an innovative design applied in subsea axial compressors, notably increases pressurization efficiency. However, its reverse rotation dynamic coupling effect introduces complex aerodynamic excitation that couple the rotors and lead to instability. In this work, a finite element model of a counter-rotating dual-rotor system, featuring inter-shaft bearing support and incorporating aerodynamic excitation effects, is developed. Through systematic analysis, the vibration characteristics under aerodynamic excitation are quantitatively evaluated, and the instability mechanisms are elucidated. Based on it, a novel vibration suppression strategy employing elastic ring magnetorheological dampers (ERMRDs) with actively adjustable stiffness and damping properties is proposed. The suppression effectiveness of excitation current variations on the vibrations of both inner and outer rotors under aerodynamic excitation is investigated. Results demonstrate that although the inherent rotor coupling generates antagonistic effects between inner and outer rotors, the ERMRD configuration achieves comprehensive vibration suppression. Notably, the ERMRD can effectively mitigate the nonsynchronous whirling induced by aerodynamic excitation, enhancing the operational stability for counter-rotating dual-rotor system.