Experimental and numerical study on the impact of inlet temperature inhomogeneity on the aerodynamic performance of a three-stage turbine

Gas turbines play an important role in power generation and propulsion. The simplification of the real-engine condition during turbine design results in substandard gas turbine performance. Further improvement in understanding of the corresponding effects is essential. At present, the mechanism of the deterioration in turbine aerodynamic performance caused by the full-annulus scale turbine inlet temperature inhomogeneity in real engine are still unclear. In this paper, the corresponding effects are investigated through both gas turbine experiments and full-annulus URANS simulation. The experimental results show that the impact of cold streak on multistage turbine efficiency is about −0.3 %, which is in good quantitative agreement with the simulation results. The simulation results also show a complex reduction of blade work extraction occurs in the cold streak. A strong correlation between angle of attack and Mach number and the deterioration of turbine efficiency is found. It is also found that the “squeezing” effect induced by the cold streak azimuthal migration capability causes differences in Mach number, through-flow capability, and flow field radial distribution on both sides of the cold streak. This paper can help to the understanding of turbine performance characteristics and can also further contribute to improve gas turbine energy efficiency.