Effect of fouling, thermal barrier coating degradation and film cooling holes blockage on gas turbine engine creep life

Abstract

Gas turbines are sometimes operated in very hostile conditions due to service exigencies. These environments are characterized by degradation modes such as fouling, thermal barrier coating degradation and blockage of cooling holes which affect the creep life of engines. Therefore this paper presents a performance-based creep life estimation model capable of predicting the impact of different forms of degradation on the creep life of gas turbines. The model comprises performance, thermal, stress, and life estimation models. High pressure turbine blade was selected as the life limiting component of the gas turbine; therefore the integrated model was employed to investigate the effect of engine degradation on the creep life of a high pressure turbine blade of an aero derivative model gas turbine engine using a Creep Factor approach. The results shows that engine degradation affect the performance of gas turbine component which in turn affect their creep life.