Numerical analysis of sealing performance for counter-rotating intershaft face gas film seals

This study proposes a stepped spiral groove configuration for counter-rotating intershaft face gas film seals to address sealing challenges in aeroengine dual-rotor bearings. The steady-state performance of this seal is investigated through mechanical analysis coupled with computational fluid dynamics. Results demonstrate that outer rotor speed critically governs axial friction on the C-shaped split sealing ring. Maximum leakage occurs when high- and low-pressure-side gas film clearances equalize. Reducing the low-pressure clearance below 6 μm triggers hydrodynamic effects, attenuated by counter-rotation. Proper matching between sealing pressure differential and rotational speed is critical for achieving self-adaptive axial floating of the seal ring. Self-adaptive axial floating requires precise sealing pressure-rotational speed matching, with minimum actuation pressures of 0.181, 0.221, and 0.261 MPa at inner/outer rotor speeds of 6000/3000, 11000/6000, and 16000/9000 r/min, respectively. The random initial position of the sealing ring may induce axial stagnation phenomena, leading to contact friction. Mismatched speed-pressure conditions degrade performance: high-speed/low-pressure scenarios lack gas film force differentials for mobility, while low-speed/high-pressure operations risk collision wear from insufficient low-pressure film support. Adaptability is enhanced by reducing rotor-seal friction and optimizing end-face geometries to improve gas film load capacity.