Investigating Al-Si base abradable material removal mechanism with axial movement in labyrinth seal system

Abstract

Modern aeroengines employ labyrinth seal systems to seal the clearance between the blade tip and surrounding engine casing. Understanding of the wear mechanism between labyrinth fins and abradable coatings on the casing is necessary to help the aeroengine achieve higher efficiency. In this study, multiple tests with different types of fin geometries are conducted on a high-speed test rig with a fin tip speed of 100m/s. Two motorized stages are used to simulate the axial movement of the labyrinth fin in an aeroengine. The wear mechanism is investigated over a range of incursion rates from 2μm/pass to 10μm/pass, with in-situ force and temperature measurements along with high-speed imaging recorded on the side in each case. The surface examination of the wear track is also employed by using microscopy post-test. The main abradable material removal mechanism is extruding from the fin side. Also, adhesion of abradable material to the fin is found in each test and the adhesion amount is affected by both fin geometry and incursion rate.