The wear mechanisms occurring in a labyrinth seal/abradable contact depending on the incursion depth parameter
1 TURBOMECA, Avenue Joseph Szydlowski,
2 Université de Toulouse, Laboratoire Génie de Production, École Nationale d’Ingénieurs de Tarbes, 47 Avenue d’Azereix, BP 1629, 65016 Tarbes Cedex, France
a Corresponding author:
Accepted: 2 December 2015
The contact behavior of an abradable coating (Al-Si 6%) and a labyrinth seal tooth (stainless steel) in a turbo-engine application was studied as a function of the incursion depth parameter, during labyrinth seal/abradable interaction. A controlled and a gradual increase of the labyrinth seal incursion (by step of 50μm) is performed to obtain the chronological contact evolution under severe operating tribological conditions. The labyrinth seal/abradable contact experiments were conducted on a dedicated test rig able to reach high contact speeds from 0 to 130 m.s-1. To complete contact forces measurement during tests, a suitable instrumentation (acoustic emission sensor, accelerometer, thermocouples, etc.) is developed and coupled as close as possible of the interaction area. The experimental results from the both severe tribological conditions are presented by an analysis of signals recorded during contact tests. Macrographic and micrographic rub-groove observations of post tests samples, coupled with recorded signals from the contact complete the Al-Si 6% behavior study. A wear process description using the third body approach has been proposed to sum up the whole tribological results. Two different varieties of particles production have been identified; a ductile and an adhering layer on the rub-groove bottom and pulverulent fine powder particles, thus providing two different kind of third body and two different material flows.
Key words: Labyrinth seal / abradable coating / wear mechanisms / third body / experimental study
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