Book Description

Abstract: As the demand for greater efficiency and reduced specific fuel consumption from gas turbine engines continues to increase, design tools must be improved to better handle complicated flow features such as vane inlet temperature distortions, film cooling, and disk purge flow. In order to understand the physics behind these features, a new generation of turbine experiments is needed to investigate these features of interest for a realistic environment. This dissertation presents for the first time measurements and analysis of the flow features of a high-pressure one and one-half stage turbine operating at design corrected conditions with vane and purge cooling as well as vane inlet temperature profile variation. It utilizes variation of cooling flow rates from independent circuits through the same geometry to identify the regions of cooling influence on the downstream blade row. The vane outer cooling circuit, which supplies the film cooling on the outer endwall of the vane and the trailing edge injection from the vane, has the largest influence on temperature and heat-flux levels for the uncooled blade. Purge cooling has a more localized effect, but it does reduce the Stanton Number deduced for the blade platform and on the pressure and suction surfaces of the blade airfoil. Flow from the vane inner cooling circuit is distributed through film cooling holes across the vane airfoil surface and inner endwall, and its injection is entirely designed with vane cooling in mind. As such, it only has a small influence on the temperature and heat-flux observed for the downstream blade row. In effect, the combined influence of these three cooling circuits can be observed for every instrumented surface of the blade. The influence of cooling on the pressure surface of the uncooled blade is much smaller than on the suction surface, but a local area of influence can be observed near the platform. This is also the first experimental program to investigate the influence of vane inlet temperature profile on a cooled turbine operating at design corrected conditions. The vane inlet temperature profile has a substantial effect on the temperature measured at the blade leading edge and the Stanton Numbers deduced for the uncooled blade airfoil. While the temperature profile is slightly reshaped passing through the vane, a radial or hot streak profile introduced at the vane inlet can still be clearly measured at the blade. Hot streak magnitude and alignment also influence the blade temperature and heat-flux measurements. A concurrent effort to predict the blade leading edge and platform temperatures for the uncooled portions of this experiment using the commercial code FINE/Turbo is also presented. This investigation is not intended as a detailed computational study but as a check of current code implementation practices and a sanity check on the data. The best predictions are generated using isothermal wall boundary conditions with the nonlinear harmonic method. This is a novel prediction type that could only be performed using a development version of FINE/Turbo.