Impact of trailing-edge modification in stator vanes on heat transfer and the performance of gas turbine: a computational study

Abstract

Despite extensive studies on the modification of airfoil profiles, most studies have primarily focused on the turbulent wave development and aerodynamic characteristics of modified airfoils. Moreover, studies considering the combined effects of hot-streak conditions at the turbine inlet and the modified profile of stator vanes on gas turbine performance are scarce. Thus, this study conducted a detailed numerical analysis to examine the effects of various trailing-edge (TE) profile modifications at the first stator vane on the heat transfer characteristics and performance of a high-pressure gas turbine. Four cases were investigated: a typical TE (without modification) as the reference case and three modification cases based on the wavelength number (TE-2, TE-4, and TE-8). The Reynolds-averaged Navier – Stokes equations coupled with the k − ω SST γ θ model were employed to solve the complex fluid flow through the 1.5-stage GE-E3 gas-turbine model. The modified cases noticeably increased the heat transfer and aerodynamic characteristics of the blade/vane surface by a maximum of approximately 1–2% owing to the effects of the TE profile on the generation of the passage vortex and secondary flow. This increased the thermal and mechanical stresses, particularly in the hub and shroud regions, which may reduce the fatigue life of the blade/vane components. Furthermore, under the effects of the first stator TE profile on the tip leakage flow, the TE-2 case exhibited a slight increase in the overall efficiency (approximately 0.15%). In contrast, the efficiencies of the other modifications decreased compared to the reference case.