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Simplified Approach to Predicting Rough Surface TransitionTurbine vane heat transfer predictions are given for smooth and rough vanes where the experimental data show transition moving forward on the vane as the surface roughness physical height increases. Consistent with smooth vane heat transfer, the transition moves forward for a fixed roughness height as the Reynolds number increases. Comparisons are presented with published experimental data. Some of the data are for a regular roughness geometry with a range of roughness heights, Reynolds numbers, and inlet turbulence intensities. The approach taken in this analysis is to treat the roughness in a statistical sense, consistent with what would be obtained from blades measured after exposure to actual engine environments. An approach is given to determine the equivalent sand grain roughness from the statistics of the regular geometry. This approach is guided by the experimental data. A roughness transition criterion is developed, and comparisons are made with experimental data over the entire range of experimental test conditions. Additional comparisons are made with experimental heat transfer data, where the roughness geometries are both regular and statistical. Using the developed analysis, heat transfer calculations are presented for the second stage vane of a high pressure turbine at hypothetical engine conditions.
Document ID
20100003158
Acquisition Source
Glenn Research Center
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Boyle, R. J.
(NASA Glenn Research Center Cleveland, OH, United States)
Stripf, M.
(Karlsruhe Univ. Germany)
Date Acquired
August 25, 2013
Publication Date
October 1, 2009
Publication Information
Publication: Journal of Turbomachinery
Publisher: American Society of Mechanical Engineers
Volume: 131
Issue: 4
Subject Category
Aircraft Propulsion And Power
Distribution Limits
Public
Copyright
Other

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