| Description |
Aerodynamic losses and discharge coefficients are obtained for two different Pratt and Whitney axisymetric turbine airfoils with film cooling holes. Blade 3 results are given for the blowing ratios, of 0.42, 0.73, and 1.28. The pressure ratios are 1.18, 1.45, and 2.07 for the "ambient" tests and 1.12, 1.19, and 1.78 for the "cold" tests. The density ratios are 0.840, 0.88, and 0.973 for the "ambient" tests and 1.130, 1.37, and 1.330 for the "cold" tests. Blade 4 results are given for the blowing ratios, of 0.248, 0.39, and 0.697. The pressure ratios are 1.197, 1.357, and 1.876 for the "ambient" tests and 1.153, 1.305, and 1.607 for the "cold" tests. The density ratios are 0.838, 0.867, and 0.95 for the "ambient" tests and 1.032, 1.127, and 1.223 for the "cold" tests. Results of qualification tests of the Transonic Wind Tunnel are also given. These include test section inlet uniformity, flow variation with time, Schlerien images of the test section flow, and the Mach number distribution along the surface of the airfoil. All tests indicate satisfactory test section and wind tunnel preformance. The integrated aerodynamic losses for Blade 3 range between .0383 and 0.51 for the "ambient" tests and between 0.411 and 0.507 for the "cold" tests. For Blade 4, the integrated aerodynamic losses range from 0.525 and 0.55 for the "ambient" tests and 0.495 and 0.538 for the "cold" tests. Integrated aerodynamic losses are generally lower with "cold" injection than with "ambient" injection for Blade 3. Blade 3 gives lower integrated aerodynamic losses compared to blade 4 when compared at the same Mach number ratio. This is attributed to the different film hole geometries of the blades. The discharge coefficients associated with the film holes on Blade 3 range from 0.94 to 1.3 for "ambient" tests and 1.07 to 1.3 for ‘‘cold" tests. The discharge coefficients associated with the film holes on Blade 4 range from 0.54 to 0.78 for "ambient" tests and 0.55 to 0.80 for "cold" tests. Hole diameters used to calculate discharge coefficients are 0.381 mm and 0.469 mm for blades 3 and 4, respectively. These diameters account for some discharge coefficient values greater than one. In all cases, discharge coefficients increase as the pressure ratio increases, and discharge coefficients measured with freestream cross flow are generally lower than values measured with no freestream cross flow, for pressure ratios less than about 1.5, when compared at the same pressure ratio. |
