The effects of freestream turbulence, turbulence length scale, and exit reynolds number on turbine blade heat transfer in a transonic cascade

J. S. Carullo, S. Nasir, R. D. Cress, W. F. Ng, K. A. Thole, L. J. Zhang, H. K. Moon

Research output: Contribution to journalArticle

31 Citations (Scopus)

Abstract

This paper experimentally investigates the effect of high freestream turbulence intensity, turbulence length scale, and exit Reynolds number on the surface heat transfer distribution of a turbine blade at realistic engine Mach numbers. Passive turbulence grids were used to generate freestream turbulence levels of 2%, 12%, and 14% at the cascade inlet. The turbulence grids produced length scales normalized by the blade pitches of 0.02, 0.26, and 0.41, respectively. Surface heat transfer measurements were made at the midspan of the blade using thin film gauges. Experiments were performed at the exit Mach numbers of 0.55, 0.78, and 1.03, which represent flow conditions below, near, and above nominal conditions. The exit Mach numbers tested correspond to exit Reynolds numbers of 6×105, 8×105, and 11×105, based on true chord. The experimental results showed that the high freestream turbulence augmented the heat transfer on both the pressure and suction sides of the blade as compared with the low freestream turbulence case. At nominal conditions, exit Mach 0.78, average heat transfer augmentations of 23% and 35% were observed on the pressure side and suction side of the blade, respectively.

Original languageEnglish (US)
Article number011030
JournalJournal of Turbomachinery
Volume133
Issue number1
DOIs
StatePublished - Jan 31 2011

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Cascades (fluid mechanics)
Turbomachine blades
Reynolds number
Turbulence
Turbines
Heat transfer
Mach number
Gages
Engines
Thin films

All Science Journal Classification (ASJC) codes

  • Mechanical Engineering

Cite this

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title = "The effects of freestream turbulence, turbulence length scale, and exit reynolds number on turbine blade heat transfer in a transonic cascade",
abstract = "This paper experimentally investigates the effect of high freestream turbulence intensity, turbulence length scale, and exit Reynolds number on the surface heat transfer distribution of a turbine blade at realistic engine Mach numbers. Passive turbulence grids were used to generate freestream turbulence levels of 2{\%}, 12{\%}, and 14{\%} at the cascade inlet. The turbulence grids produced length scales normalized by the blade pitches of 0.02, 0.26, and 0.41, respectively. Surface heat transfer measurements were made at the midspan of the blade using thin film gauges. Experiments were performed at the exit Mach numbers of 0.55, 0.78, and 1.03, which represent flow conditions below, near, and above nominal conditions. The exit Mach numbers tested correspond to exit Reynolds numbers of 6×105, 8×105, and 11×105, based on true chord. The experimental results showed that the high freestream turbulence augmented the heat transfer on both the pressure and suction sides of the blade as compared with the low freestream turbulence case. At nominal conditions, exit Mach 0.78, average heat transfer augmentations of 23{\%} and 35{\%} were observed on the pressure side and suction side of the blade, respectively.",
author = "Carullo, {J. S.} and S. Nasir and Cress, {R. D.} and Ng, {W. F.} and Thole, {K. A.} and Zhang, {L. J.} and Moon, {H. K.}",
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The effects of freestream turbulence, turbulence length scale, and exit reynolds number on turbine blade heat transfer in a transonic cascade. / Carullo, J. S.; Nasir, S.; Cress, R. D.; Ng, W. F.; Thole, K. A.; Zhang, L. J.; Moon, H. K.

In: Journal of Turbomachinery, Vol. 133, No. 1, 011030, 31.01.2011.

Research output: Contribution to journalArticle

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AU - Zhang, L. J.

AU - Moon, H. K.

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