The present study is an experimental investigation of film cooling from cylindrical holes embedded in transverse trenches. Different trench depths are considered with two trench widths. Trench holes can occur when blades are coated with thermal barrier coating (TBC) layers. The film-hole performance and behavior will be different for the trench holes compared to standard cylindrical holes that are flush with the surface. The trench width and depth depend on the mask region and the thickness of the TBC layer. Detailed heat transfer coefficient and film effectiveness measurements are obtained simultaneously using a single test transient IR thermography technique. The study is performed at a single mainstream Reynolds number based on freestream velocity and film-hole diameter of 11,000 at four different coolant-to-mainstream blowing ratios of 0.5, 1.0, 1.5, and 2.0. The results show that film effectiveness is greatly enhanced by the trenching due to the improved two-dimensional nature of the film and lateral spreading. The detailed heat transfer coefficient and film effectiveness contours provide a clear understanding of the jet-mainstream interactions for different hole orientations. Computational fluid dynamics simulation using FLUENT was also performed to determine the jet-mainstream interactions to better understand the surface heat transfer coefficient and film effectiveness distributions.
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January 2009
Research Papers
Effect of Trench Width and Depth on Film Cooling From Cylindrical Holes Embedded in Trenches
Yiping Lu,
Yiping Lu
Mechanical Engineering Department,
Virginia Tech
, Blacksburg, VA 24061
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Alok Dhungel,
Alok Dhungel
Mechanical Engineering Department,
Virginia Tech
, Blacksburg, VA 24061
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Ronald S. Bunker
Ronald S. Bunker
GE Global Research Center
, Niskayuna, NY 12301
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Yiping Lu
Mechanical Engineering Department,
Virginia Tech
, Blacksburg, VA 24061
Alok Dhungel
Mechanical Engineering Department,
Virginia Tech
, Blacksburg, VA 24061
Srinath V. Ekkad
Ronald S. Bunker
GE Global Research Center
, Niskayuna, NY 12301J. Turbomach. Jan 2009, 131(1): 011003 (13 pages)
Published Online: September 25, 2008
Article history
Received:
June 11, 2007
Revised:
July 13, 2007
Published:
September 25, 2008
Citation
Lu, Y., Dhungel, A., Ekkad, S. V., and Bunker, R. S. (September 25, 2008). "Effect of Trench Width and Depth on Film Cooling From Cylindrical Holes Embedded in Trenches." ASME. J. Turbomach. January 2009; 131(1): 011003. https://doi.org/10.1115/1.2950057
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