Trailing edge of a gas turbine blade is under very high thermal load because both sides are exposed to hot mainstream. The cooling film ejected from slots has to protect the cutback surface from the hot mainstream, and remove the heat from the surface. In this study, the film cooling performance of cutback surfaces with two types of dimples, spherical and teardrop-shaped dimples, were experimentally investigated with a transient infrared thermography method. Also, to examine the effects of arrangements, two different arrangements of the teardrop-shaped dimples, which are parallel and inclined to mainstream, were investigated. The dimples were arranged in two rows on the cutback surfaces. The Reynolds number of mainstream defined by the mean velocity and hydraulic diameter was 20,000, and profiles of local heat transfer coefficient and film cooling effectiveness on the cutback surface were measured for blowing ratios of 0.5–2.0. With the parallel teardrop-shaped dimples, reduction of the heat transfer in the upstream portion was less than that of the spherical dimples, and the heat transfer at downstream rims was higher. In the case of the inclined teardrop-shaped dimples, heat transfer enhancement at the downstream rims was higher than that of parallel one, and overall heat transfer coefficient was also higher. The film cooling effectiveness of all cases are almost equal values, namely, the dimpled surfaces could enhance heat transfer without reduction of the film cooling effectiveness; consequently significant cooling performance improvement was obtained for the teardrop-shaped dimple cases, especially with the introduction of inclined arrangement.
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ASME Turbo Expo 2013: Turbine Technical Conference and Exposition
June 3–7, 2013
San Antonio, Texas, USA
Conference Sponsors:
- International Gas Turbine Institute
ISBN:
978-0-7918-5515-7
PROCEEDINGS PAPER
Effects of Shape and Arrangement of Dimples on Film Cooling Performance Over Cutback Surface at Airfoil Trailing Edge
Satomi Nishida,
Satomi Nishida
IHI Corporation, Tokyo, Japan
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Akira Murata,
Akira Murata
Tokyo University of Agriculture & Technology, Koganei, Tokyo, Japan
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Hiroshi Saito,
Hiroshi Saito
Tokyo University of Agriculture & Technology, Koganei, Tokyo, Japan
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Chiyuki Nakamata,
Chiyuki Nakamata
IHI Corporation, Tokyo, Japan
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Kaoru Iwamoto
Kaoru Iwamoto
Tokyo University of Agriculture & Technology, Koganei, Tokyo, Japan
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Satomi Nishida
IHI Corporation, Tokyo, Japan
Akira Murata
Tokyo University of Agriculture & Technology, Koganei, Tokyo, Japan
Hiroshi Saito
Tokyo University of Agriculture & Technology, Koganei, Tokyo, Japan
Yoji Okita
IHI Corporation, Tokyo, Japan
Chiyuki Nakamata
IHI Corporation, Tokyo, Japan
Kaoru Iwamoto
Tokyo University of Agriculture & Technology, Koganei, Tokyo, Japan
Paper No:
GT2013-95542, V03BT13A054; 13 pages
Published Online:
November 14, 2013
Citation
Nishida, S, Murata, A, Saito, H, Okita, Y, Nakamata, C, & Iwamoto, K. "Effects of Shape and Arrangement of Dimples on Film Cooling Performance Over Cutback Surface at Airfoil Trailing Edge." Proceedings of the ASME Turbo Expo 2013: Turbine Technical Conference and Exposition. Volume 3B: Heat Transfer. San Antonio, Texas, USA. June 3–7, 2013. V03BT13A054. ASME. https://doi.org/10.1115/GT2013-95542
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