Influence of Mainstream Turbulence Intensity on Heat Transfer Characteristics of a HP Turbine Stage With Inlet Hot Streak

Abstract

An unsteady computational study were carried out for the GE-E3 HP turbine at inflow turbulence intensities of 5%, 10% and 20% accompanying with inlet hot streak (HS) at two circumferential positions (impinging and non-impinging relative to vane leading edge) to analyze the interacted turbulence and HS influences. Several validation studies were performed to investigate the heat transfer prediction ability of shear stress transport (SST) turbulence model coupled with γ-θ transition model. Turbulence decay mechanisms in turbine passage were presented, and the airfoil heat transfer behaviors were explored by means of both time-averaged adiabatic wall temperature and heat transfer coefficient (HTC). The results indicate that increase of inflow turbulence leads to favorable turbine temperature distributions in general, and on the blade and tip surface in particular, especially for the non-impinging case and inflow turbulence increasing from 10% to 20%. While the vane and blade surface area-averaged temperatures are hardly changed, a maximum area-averaged temperature drop of 8.9 K is induced at the tip surface. Higher HTC is observed at vane, blade pressure surface, and suction surface mid region at higher turbulence. However, HTCs at endwall regions of blade suction surface and blade tip are insensitive to the turbulence effect, thus the heat load of these regions is not critical when the inflow turbulence intensity is increased. HS position not only affects the airfoil surface temperature variations, but also slightly affects the vane and blade midspan HTC for the variation of fluid driving temperature.