Abstract
Labyrinth seals as a noncontact sealing technology are widely used in aero-engine. To improve the efficiency of the aero-engine, the clearance between the rotor and stator must be as small as possible. However, the change of the clearance between the rotor and stator because of thermal expansion, vibration, mechanical loading may lead to undesirable high-speed rub, which will lead to the cracking of the seal fins. This paper focuses on the wear of the seal fin after the rub and presents the rubbing tests between seal fins and the metal honeycomb under rubbing speed of 380 m/s and incursion rates between 20 and 180 μm/s, with an incursion depth of 1500 μm and a temperature of 350 °C. The rubbing force and temperature were recorded, and the seal fins were checked by SEM and EDS. The results show that the wear mechanism of seal fins changed from oxidation wear and adhesive wear to delamination wear and then to metal wear with the increasing incursion rate. The axial cracks appeared on the worn surface of the seal fins due to the cracking of tribo-layers under periodic thermomechanical stress. The wear mechanism of the seal fin also has a great influence on the rubbing force and temperature.
Highlights
Increasing engine effectiveness and reducing leakages are the main goals for the development of aero-engines
Labyrinth seals, which have several teeth on the rotation part, as noncontact sealing technology are still widely used in aero-engines [1,2]
The results demonstrated that aluminide-coated honeycomb tended to stick more to the seal fins during the rub, and the wear of the seal fin was uneven
Summary
Increasing engine effectiveness and reducing leakages are the main goals for the development of aero-engines. Labyrinth seals, which have several teeth on the rotation part, as noncontact sealing technology are still widely used in aero-engines [1,2]. They have many advantages, such as a simple design, long lifetime, and applicability under extreme operating conditions [3]. Choosing the appropriate materials, such as Hastelloy X, can result in the honeycomb having good erosion, corrosion, and oxidation resistances. These characteristics are important to maintain the mechanical properties of the honeycomb under extreme operating conditions [4]
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