Investigation of high-temperature blade wear in ceramic abradable seals under representative gas turbine conditions through a novel heated incursion rig

To optimise gas turbine aerodynamic efficiency, High-Pressure Turbine (HPT) stages use ceramic abradable seals that interact with abrasive-tipped blades. Evaluating the wear mechanisms of these systems requires simultaneous high-speed and high-temperature conditions, which are difficult to achieve in standard testing facilities. This study presents the development and validation of a High-Temperature Rig (HTR) that integrates high-speed rotor dynamics (100 m s-1) with an induction heating system targeted at the blade to simulate engine incursion under high-temperature conditions on the blade tip side of high-pressure turbines. The achievement of engine-representative wear mechanisms in the HTR, benchmarked against an established room-temperature rig (SR), confirmed that ambient conditions yield a stable cutting interaction governed by brittle fracture. However, testing under representative temperatures showed a vulnerability in the electroplated c-BN abrasive coating. High temperatures cause the abradable material to adhere to the blade, reducing cutting efficiency and increasing normal contact forces up to 13 kN at high incursion rates. Topographical analysis using Positive Volume Variation (PVV) metrics demonstrated that this material congestion causes the abrasive layer to structurally collapse, transitioning the contact to pure friction. Results indicate that high-speed blade performance is limited not by mechanical grit wear, but by the thermal stability of the metallic anchoring matrix, which yields plastically when it reaches a friction-induced thermal limit near 1100 °C.