Bench-scale testing study on the influence of surface texturing on leakage performance and tribological properties of finger seals

Abstract This study investigates the effects of surface texturing on the leakage and tribological performance of finger seals via bench-scale experiments to address the aeroengine dynamic sealing requirements. Circular array textures (10% density, 200 μm diameter) were fabricated on rotor raceways. The tests included static leakage (ambient/450 °C) and dynamic variable-speed tests under constant pressure. Laser confocal interferometry characterizes wear morphologies to reveal texture-sealing mechanisms. The results show that texturing reduces leakage by 15% compared to non-textured surfaces, which is attributed to the enhanced gas-film hydrodynamic pressure. The texture inhibition of the leakage growth intensifies with higher pressure differentials. Rotor speed elevations further reduce leakage via aerodynamic and levitation effects, although deceleration hysteresis increases leakage. This is mitigated by a wide-temperature wear coating at 450 °C. Tribological analysis shows that textures decrease wear scar width/roughness by debris trapping and stress reduction, shifting wear from severe abrasive/adhesive (nontextured) to mild abrasive (textured). These findings validate textured finger seals for extremely high-T/speed applications, confirming texturing as a strategy for concurrent leakage control and tribological optimization.