Dominant parameters affecting the reliability of TBCs on a gas turbine blade during erosion by a particle-laden hot gas stream

Abstract

Thermal barrier coatings (TBCs) with high brittleness usually exhibit uncertain lifetime due to their scattered mechanical properties and severe service conditions. Here we establish a method of assessing the reliability and the dominant parameters affecting the reliability of TBCs deposited onto a turbine blade substrate during erosion by a hot gas stream. An erosion rate model is established to analyse the failure of TBCs induced by a single solid particle. The velocity, angle, and erosion location of foreign particles attacking the TBCs in a hot gas stream are calculated via numerical simulation, and the distribution of erosion rate is obtained according to the erosion rate model of a single particle. Additionally, reliability methods along with sensitivity analysis are used to quantitatively assess the reliability of TBCs. The results indicate that the most significant parameter affecting the reliability is the pressure at turbine outlet, followed by the coating thickness and the rotational speed of rotor, while both exhibit more obvious effect than the lamella thickness. Moreover, possible approaches to improve the reliability of TBCs are also proposed based on the modeling study.