Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1979. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND AERONAUTICS. / Vita. / Includes bibliographical references. / Ph.D.

Gas turbine blade tip heat transfer and tip gap flow phenomena has been explored experimentally in a stationary cascade for blade exit Mach numbers = 1.2 to 1.4. Experimental results were found to agree well with qualitative predictions performed at GE Aircraft Engines. The pressure distribution in the blade tip cavity of a grooved tip blade was found to vary little with either Mach number or tip gap height. The tip cavity pressure was, however, a strong function of location. The tip cavity pressure distribution coupled with the pressure side distribution near the tip was speculated to drive the leakage flow across the blade tip from mid-chord aft based on surface flow visualization studies using an oil/dye mixture. Heat flux on the tip cavity floor was successfully measured using a thin-film Heat Flux Microsensor. Results of these measurements are consistent with previous studies in the subsonic regime. The convection coefficients on the tip cavity floor were found to be three times those found on the suction side airfoil surface near the trailing edge. Convection coefficients were found not to vary with either tip gap height or Mach number. The fluctuating component of heat flux was found to be at least 25% of the total heat flux. / Master of Science

The aerodynamic and thermodynamic performance of an aircraft gas turbine directly affects the fuel consumption of the engine and the life of the turbine components. Hence, it is important to be able to understand and predict the fluid flow and heat transfer in turbine blades to enable the modifications and improvements in the design process. The use of numerical experiments for the above purposes is becoming increasingly common. The present thesis is involved with the development of a flow solver for turbine flow and heat transfer computations. A 3-D Navier-Stokes code, the Moore Elliptic Flow Program (MEFP) is used to calculate steady flow and heat transfer in turbine rotor cascades. Successful calculations were performed on two different rotor profiles using a one-equation q-L transitional turbulence model. A series of programs was developed for the post-processing of the output from the flow solver. The calculations revealed details of the flow including boundary layer development, trailing edge shocks, flow transition and stagnation and peak heat transfer rates. The calculated pressure distributions, losses, transition ranges, boundary layer parameters and peak heat transfer rates to the blade are compared with the available experimental data. The comparisons indicate that the q-L transitional turbulence model is successful in predicting flows in transonic turbine blade rows. The results also indicate that the calculated loss levels are independent of the gridding used while the heat transfer rate predictions improve with finer grids. / Master of Science