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Measurements of 3D velocity and scalar field for a film-cooled airfoil trailing edge

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Abstract

The 3D velocity and concentration fields have been measured for flow in a pressure side cutback trailing edge film cooling geometry consisting of rectangular film cooling slots separated by tapered lands. The velocity field was measured using conventional magnetic resonance velocimetry, and the concentration distribution was measured with a refined magnetic resonance concentration technique that yields experimental uncertainties for the concentration between 5 and 6%. All experiments were performed in water. A separation bubble behind the slot lip entrains coolant and promotes rapid turbulent mixing at the upper edge of the coolant jet. Vortices from inside the slot feed channel and on the upper sides of the lands rapidly distort the initially rectangular shape of the coolant stream and sweep mainstream flow toward the airfoil surface. The vortices also prevent any coolant from reaching the upper surfaces of the land. At the trailing edge, a second separation region exists in the blunt trailing edge wake. The flow forms suction side streaks behind the land tips, as well as streaks behind the slot centers on the pressure side. The peak coolant concentrations in the streaks remain above 25% through the end of the measurement domain, over 30 slot heights downstream.

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Acknowledgments

Financial support for the project was provided by General Electric under the University Strategic Alliance program. In addition, this material is based upon work supported in part by the U. S. Army Research Laboratory and the U. S. Army Research Office under contract/grant number 57392-EG-II. Use of the facilities at the Richard M. Lucas Center for Magnetic Resonance Spectroscopy and Imaging is gratefully acknowledged. The authors wish to thank the United States Army for funding the first author in his doctoral studies at Stanford. The views expressed herein are those of the authors and do not purport to reflect the position of the Department of the Army, or the Department of Defense.

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Authors and Affiliations

  1. Department of Mechanical Engineering, Stanford University, Stanford, CA, 94305, USA

    Michael J. Benson, Christopher J. Elkins & John K. Eaton

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  1. Michael J. Benson
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  2. Christopher J. Elkins
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  3. John K. Eaton
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Correspondence to Michael J. Benson.

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Benson, M.J., Elkins, C.J. & Eaton, J.K. Measurements of 3D velocity and scalar field for a film-cooled airfoil trailing edge. Exp Fluids 51, 443–455 (2011). https://doi.org/10.1007/s00348-011-1062-x

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  • DOI: https://doi.org/10.1007/s00348-011-1062-x

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