Interactions between embedded vortices and injectant from film cooling holes with compound angle orientations in a turbulent boundary layer

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Authors
Ligrani, P.M.
Mitchell, S.W.
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1994-01-01
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Abstract
Experimental results are presented that describe the effects of embedded, longitudinal vortices on heat transfer and film injectant downstream of two staggered rows of film cooling holes with compound angle orientations. Holes are oriented so that their angles with respect to the test surface are 30 deg in a spanwise/normal plan projection, and 35 deg in a streamwise/normal projection. A blowing ratio of 0.5, nondimensional injection temperature parameter [theta] of about 1.5, and free-stream velocity of 10 m/s are employed. Injection hole diameter is 0.945 cm to give a ratio of vortex core diameter to hole diameter of 1.6--1.67 just downstream of the injection holes (x/d = 10.2). At the same location, vortex circulation magnitudes range from 0.15 m[sup 2]/s to 0.18 m[sup 2]/s. By changing the sign of the angle of attack of the half-delta wings used to generate the vortices, vortices are produced that rotate either clockwise or counterclockwise when viewed looking downstream in spanwise/normal planes. The most important conclusion is that local heat transfer and injectant distributions are strongly affected by the longitudinal embedded vortices, including their directions of rotation and their spanwise positions with respect to film injection holes. Differences resulting from vortex rotation are due to secondary flow vectors, especially beneath vortex cores, which are in different directions with respect to the spanwise velocity components of injectant after it exits the holes. Surveys of streamwise mean velocity, secondary flow vectors, total pressure, and streamwise mean vorticity are also presented that further substantiate these findings.
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Naval Postgraduate School (U.S.)
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Journal Name: Journal of Turbomachinery; (United States); Journal Volume: 116:1; Conference: 37. international gas turbine and aeroengine congress and exposition - ASME turbo expo: land, sea, and air, Cologne (Germany), 1-4 Jun 1992
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This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.
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