Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 3 of 3
Full-Text Articles in Engineering
Use Of Dimples To Suppress Boundary Layer Separation On A Low Pressure Turbine Blade, Kurt P. Rouser
Use Of Dimples To Suppress Boundary Layer Separation On A Low Pressure Turbine Blade, Kurt P. Rouser
Theses and Dissertations
Flow separation on a low pressure turbine blade is explored at Reynolds numbers of 25k, 45k and 100k. Experimental data is collected in a low-speed, draw-down wind tunnel using a cascade of eight Pak-B blades. Flow is examined from measurements of blade surface pressures, boundary layer parameters, exit velocities, and total pressure losses across the blade. Two recessed dimple shapes are assessed for suppressing flow separation and associated losses. One dimple is spherical, and the second is asymmetric, formed from a full dimple spanwise half-filled. A single row of each dimple shape is tested at 50%, 55% and 65% axial …
The Combined Effects Of Freestream Turbulence, Pressure Gradients, And Surface Roughness On Turbine Aerodynamics, Christine P. Ellering
The Combined Effects Of Freestream Turbulence, Pressure Gradients, And Surface Roughness On Turbine Aerodynamics, Christine P. Ellering
Theses and Dissertations
This work used scaled facsimiles of real turbine blade surfaces to characterize correlations between turbine blade roughness, freestream turbulence, pressure gradients and skin friction (Cf). Addition of roughness caused Cf to increase: up to 300% for the roughest surface. Addition of freestream turbulence resulted in 125% increase for the same surface. The combined effects showed increases up to 380%. Although decreasing roughness, freestream turbulence, and Reynolds number resulted in less dramatic results, it was concluded that the Cf increases due to combined effects were consistently higher than their corresponding sum of the parts. The combined effects of roughness and pressure …
The Influence Of Surface Roughness On Supersonic High Reynolds Number Turbulent Boundary Layer Flow, Robert M. Latin
The Influence Of Surface Roughness On Supersonic High Reynolds Number Turbulent Boundary Layer Flow, Robert M. Latin
Theses and Dissertations
A comprehensive study of rough-wall high speed (M=2.9) high Reynolds number (Re/m = 1.9 x 107) turbulent boundary layer flow was performed consisting of experimental, analytical, and numerical methods. Six wall topologies consisting of a smooth and five rough surfaces (two and three dimensional machined roughness plates; and 80, 36, and 20 grit sand-grain roughened plates) were studied. A confocal laser scan microscope was used to measure the topography of the sand grain roughnesses. The experimental measurement techniques included a convention Pitot pressure probe, laser Doppler velocimetry, hot wire anemometry; color schlieren and laser …