TY - GEN
T1 - A comparison of cylindrical and fan-shaped film-cooling holes on a vane endwall at low and high freestream turbulence levels
AU - Colban, W.
AU - Thole, K. A.
AU - Haendler, M.
PY - 2006
Y1 - 2006
N2 - Fan-shaped film-cooling holes have been shown to provide superior cooling performance to cylindrical holes along flat-plates and turbine airfoils over a large range of different conditions. Benefits of fan-shaped holes include less required cooling air for the same performance, increased part lifetime, and fewer required holes. The major drawback however, is increased manufacturing cost and manufacturing difficulty, particularly for the vane platform region. To this point, there have only been extremely limited comparisons between cylindrical and shaped holes on a turbine endwall at either low or high freestream turbulence conditions. This study presents film-cooling effectiveness measurements on an endwall surface in a large-scale, low-speed, two-passage, linear vane cascade. Results showed that film-cooling effectiveness decreased with increasing blowing rate for the cylindrical holes, indicating jet lift-off. However, the fan-shaped passage showed increased film-cooling effectiveness with increasing blowing ratio. Overall, fan-shaped holes increased film-cooling effectiveness by an average of 75% over cylindrical holes for constant cooling flow.
AB - Fan-shaped film-cooling holes have been shown to provide superior cooling performance to cylindrical holes along flat-plates and turbine airfoils over a large range of different conditions. Benefits of fan-shaped holes include less required cooling air for the same performance, increased part lifetime, and fewer required holes. The major drawback however, is increased manufacturing cost and manufacturing difficulty, particularly for the vane platform region. To this point, there have only been extremely limited comparisons between cylindrical and shaped holes on a turbine endwall at either low or high freestream turbulence conditions. This study presents film-cooling effectiveness measurements on an endwall surface in a large-scale, low-speed, two-passage, linear vane cascade. Results showed that film-cooling effectiveness decreased with increasing blowing rate for the cylindrical holes, indicating jet lift-off. However, the fan-shaped passage showed increased film-cooling effectiveness with increasing blowing ratio. Overall, fan-shaped holes increased film-cooling effectiveness by an average of 75% over cylindrical holes for constant cooling flow.
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U2 - 10.1115/GT2006-90021
DO - 10.1115/GT2006-90021
M3 - Conference contribution
AN - SCOPUS:33750891857
SN - 079184238X
SN - 9780791842386
T3 - Proceedings of the ASME Turbo Expo
SP - 25
EP - 35
BT - Proceedings of the ASME Turbo Expo 2006 - Power for Land, Sea, and Air
T2 - 2006 ASME 51st Turbo Expo
Y2 - 6 May 2006 through 11 May 2006
ER -