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Modern aero-engines use abradable linings to reduce axial gas leakage. In this study the wear performance of a new developed nickel superalloy honeycomb abradableliningwas investigated on a novel high-speed test rig, using in-situ measurement techniques, combined with post-test microscopy and X-ray fluorescence based elemental analysis. In particular the effect of changing the nickel-aluminide filler ratio was considered, as well as the impact of thermal ageing of the specimens. Compaction of abradable occurs, resulting in fin wear, along with high forces and temperatures. This wear mechanism is cyclic with debris ejection and sparks. Ageing of the abradable generally leads to an increase in fin wear, with the exception that in one case this lead to improved fracture of the abradable and an improved cutting performance by the fin.

Labyrinth seal systems are used in aeroengines to seal the clearance, the understanding of the wear mechanism of labyrinth seal system is necessary to achieve better sealing performance. In this work a series of tests are conducted on a high-speed test rig capable of fin tip speeds of 100 m/s. With force and temperature measurements recorded in each case, the influence of specimen geometry is investigated. Surface examination and debris analysis is also performed using microscopy post-test. The wear mechanism was found to be influenced by fin geometry. A discrete fin was observed to trigger a more efficient material removal mechanism at both incursion conditions. Where the fin segment and ring-shaped fin leading to increased temperatures and material smearing. The heat dissipate role of fin was also observed during test where longer contact time of fin and abradable gives better heat removal performance.

Abradable liner materials are often used in turbine engines between the compressor blade tips and the casing. The abradable liner serves as a partially sacrificial material to improve the overall engine efficiency by creating a tight seal, minimising gas flow leakage. During operation, the rubbing interaction between the blade tips and abradable lined casing induces vibrations in the blades. These vibrations not only can have a significant influence on the wear mechanism and wear efficiency of the blade tips, but also the early fatigue failure of the blades, and therefore are of interest. In this paper, a newly developed approach is presented that can be used to identify the operational blade vibration modes. A non-contact single point laser sensor is used to measure the vibrational displacements during the wear process. A mathematical transform is introduced to correct for blade position due to its rotating frame of reference. After applying the transform, the vibrational energy is calculated at various positions throughout the blade. The continuous wavelet-based modal identification is then introduced to identify the blade mode shape. The Modal Assurance Criterion (MAC) is used to demonstrate the similarity of the mode shapes as a function of wear time illustrating that the blade mode shapes change slightly with the level of wear.

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