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Three-dimensional solutions of the Navier-Stokes equations for a turbine blade with a turning angle of 180 degrees have been computed, including blade tip treatments involving cavities. The geometry approximates Pratt&Whitney's preliminary design for the GGOT (Generic Gas Oxidizer Turbine). The data presented here will be used as a means of comparison for experimental data to be obtained from a linear cascade being built and tested at The University of Alabama, using the original GGOT blades. Results have been computed for a blade with 1% clearance, based on chord, and three different cavity sizes. All tests were conducted at a Reynolds number of 4x107/m. The grid contains 39,440 points with 10 spanwise planes in the tip clearance region of 5.008E-04 m. Streamline plots and velocity vectors, together with velocity divergence plots reveal the general flow behavior in the clearance region.

A study was undertaken to improve the prediction of heat transfer coefficients on the suction surface of turbine blades. The study specifically investigated the effects of coupling turbulent Prandtl number models with boundary layer transition models. A two-dimensional boundary layer code, STAN5, was selected and the turbulence model modified by incorporating several turbulent Prandtl number and boundary layer transition models found in the literature. Results indicated that subtle effects were attributable to the modified turbulence model. However, desired improvements were not obtained in the heat transfer coefficient predictions. It appears that boundary layer transition models predicting natural transition are not appropriate for use in a turbine blade flow field.

A study was undertaken to improve the prediction of external (gas-to-blade) heat transfer coefficients in gas turbine engines. The study specifically investigated the effects of improved modeling of the eddy diffusivity of heat in the turbulence model. A two- dimensional boundary layer code, STAN5, was selected and modified by incorporating several different turbulent Prandtl number models. Results indicated that slight effects were attributable to the modified turbulence model. Boundary layer character (laminar, turbulent or transitioning) appeared to be much more significant.