Effects of Hot Streak and Airfoil Clocking on Heat Transfer and Aerodynamic Characteristics in Gas Turbine

摘要

The effects of the hot streak and airfoil clocking on the heat transfer and aerodynamic characteristics in a high pressure (HP) gas turbine have been investigated in this paper. The blade geometry is taken from the first 1.5 stage turbine of GE-E~3 engine. To study the effect of hot streak clocking, three cases under nonuniform and uniform inlet temperature boundary conditions were simulated first. Subsequently, four clocking positions (CPs) of S2 (second stator) were arranged in these three cases to study the combined effect of hot streak and airfoil clocking. By solving the unsteady compressible Reynolds-averaged Navier-Stokes (RANS) equations, time-dependent solutions for the flow and heat transfer characteristics of the 1.5 stage turbine were obtained. The results indicate that impinged by different inlet temperature profiles, the heat flux distribution on S1 (first stator) blade varies significantly. Due to the separation of hot and cold fluid, more hot fluid flows toward pressure side (PS) of R1 (first rotor) and worsens the heat transfer environment there. The high heat flux on the R1 blade surface is controlled not only by the high heat transfer coefficient but also by the large temperature difference. By adjusting the CPs of S2, the hot streak fragments from the upstream could be guided to different places in S2 passage, to reduce the heat load on S2 blade surface. In view of the influence of the heat transfer characteristics, the nonadiabatic efficiency is calculated. The combined effects of the hot streak and airfoil clocking have been discussed, and the proper matching position for the two kinds of clocking could be selected for a higher nonadiabatic efficiency and lower heat load on S2 blade and end walls.