Date of Award
Master of Science
Department of Aeronautics and Astronautics
Paul I. King, PhD
The effects of changing the blade tip clearances on the velocity and pressure flowfields within a compressor cascade were investigated in this experimental thesis. All moving endwall measurements were taken at a constant flow coefficient of 0.5 and tip clearances of 0.5, 1.0 and 2.0 percent chord. Hot-wire/film probes were used to determine the three-dimensional velocity vector components in various transverse planes - one upstream of the leading edges of the blades, three within the blade cascade and one downstream of the trailing edges of the blades. The transverse velocity vector plots showed a scraping of the tip leakage vortex from the suction surface of one blade across the blade pitch to the pressure surface of the adjacent blade. A total pressure rake placed downstream of the trailing edges of the blades measured the pressure flowfield at the exit of the cascade. The mass-averaged values of total pressure loss coefficient decreased for reduced gaps. Finally, the tests performed on a crenulate blade geometry at a tip clearance of 0.01 chord showed a 15.5% reduction in the total pressure losses as compared to the straight blade geometry.
DTIC Accession Number
McMullan, Richard J., "Influence of Tip Clearance on the Flowfield in a Compressor Cascade with a Moving Endwall" (1996). Theses and Dissertations. 5841.