Failure analysis and reliability assessment of a type of aero-engine combustion chamber thermal barrier coatings

Abstract

During a routine hole probe inspection, the aviation division found that the combustion chamber flame tube of a V2500 aero engine had failed early and that the TBCs around the vent holes on the flame tube liner panel 4 had peeled off over a large area, causing the flame tube liner to burn through. This work studies the premature failure of the V2500 aero-engine flame tube and, using modeling and simulation tests, finds the reason for premature failure as a substantial area of thermal barrier coating peeling owing to sintering. The sintering procedure significantly increases the thermal barrier coating's Young's modulus, which reduces the coating's resistance to thermal mismatch strain. The reliability of the TBCs was then evaluated using a probabilistic approach. Owing to the non-uniformity of temperature distribution induced by the hot airflow, the lifetime of the TBCs in the high temperature region is only around 3000 h, but the lifetime in the low temperature region is at least 25,000 h. Using the method of hole-probing, the values of the calculated and real outcomes are compared. The relative error is less than 5 %, demonstrating that the suggested approach for evaluating dependability has high credibility and applicability.