Analysis of the thermal insulation performance of turbine blade thermal barrier coatings considering inlet non-uniformity

Abstract

The gases discharged from the new generation of lean-burn combustors usually have hot streaks (HS) and swirls. The thermal performance of rotor thermal barrier coatings (TBCs) exhibits significant non-constant behavior due to inlet non-uniformity and blade row interaction. To investigate the non-constant thermal insulation performance of the blade TBCs, non-constant numerical simulations were carried out for the first stage vane and blade of the High-pressure turbine of the GE-E3 engine. The normalized temperature results for the HS and the combination of HS and swirl cases were compared with the uniform inlet case to investigate the effect of inlet non-uniformity on the surface temperature and thermal insulation effect of the blade TBCs. The results show that a credible investigation of rotor TBCs should consider the unsteady blade row interaction. HS causes high-temperature hot spots on the surface of the TBCs and redistributes them with the change in the direction of the swirl. HS and swirl significantly reduce the turbine blade cooling effectiveness and thermal insulation effectiveness of TBCs. The lowest overall cooling performance of the blades was observed during the 1/4 T stator period. The added swirl reduces the insulation effectiveness's fluctuation value by reducing positive swirl (PSW) by 52.6 % and negative swirl (NSW) by 57.8 %. Therefore, applications and designs of TBCs should consider the effects of HS and swirl.

Keywords

• Thermal barrier coatings
• Hot streak
• Swirl
• Hot spot
• Thermal insulation effectiveness