Establishing a methodology for resolving convective heat transfer from complex geometries

Jason K. Ostanek, J. Prausa, A. Van Suetendael, Karen A. Thole

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Current turbine airfoils must operate at extreme temperatures, which are continuously driven higher by the demand for high output engines. Internal cooling plays a key role in the longevity of gas turbine airfoils. Ribbed channels are commonly used to increase heat transfer by generating turbulence and to provide a greater convective surface area. Because of the increasing complexity in airfoil design and manufacturing, a methodology is needed to accurately measure the convection coefficient of a rib with a complex shape. Previous studies that have measured the contribution to convective heat transfer from the rib itself have used simple rib geometries. This paper presents a new methodology to measure convective heat transfer coefficients on complex ribbed surfaces. The new method was applied to a relatively simple shape so that comparisons could be made with a commonly accepted method for heat transfer measurements. A numerical analysis was performed to reduce experimental uncertainty and to verify the lumped model approximation used in the new methodology. Experimental measurements were taken in a closedloop channel using fully rounded discontinuous skewed ribs oriented 45 deg to the flow. The channel aspect ratio was 1.7:1 and the ratio of rib height to hydraulic diameter was 0.075. Heat transfer augmentation levels relative to a smooth channel were measured to be between 4.7 and 3 for Reynolds numbers ranging from 10,000 to 100,000.

Original languageEnglish (US)
Article number031014
JournalJournal of Turbomachinery
Volume132
Issue number3
DOIs
StatePublished - Jul 1 2010

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Airfoils
Heat transfer
Geometry
Heat transfer coefficients
Gas turbines
Numerical analysis
Aspect ratio
Reynolds number
Turbulence
Turbines
Hydraulics
Engines
Cooling
Temperature

All Science Journal Classification (ASJC) codes

  • Mechanical Engineering

Cite this

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abstract = "Current turbine airfoils must operate at extreme temperatures, which are continuously driven higher by the demand for high output engines. Internal cooling plays a key role in the longevity of gas turbine airfoils. Ribbed channels are commonly used to increase heat transfer by generating turbulence and to provide a greater convective surface area. Because of the increasing complexity in airfoil design and manufacturing, a methodology is needed to accurately measure the convection coefficient of a rib with a complex shape. Previous studies that have measured the contribution to convective heat transfer from the rib itself have used simple rib geometries. This paper presents a new methodology to measure convective heat transfer coefficients on complex ribbed surfaces. The new method was applied to a relatively simple shape so that comparisons could be made with a commonly accepted method for heat transfer measurements. A numerical analysis was performed to reduce experimental uncertainty and to verify the lumped model approximation used in the new methodology. Experimental measurements were taken in a closedloop channel using fully rounded discontinuous skewed ribs oriented 45 deg to the flow. The channel aspect ratio was 1.7:1 and the ratio of rib height to hydraulic diameter was 0.075. Heat transfer augmentation levels relative to a smooth channel were measured to be between 4.7 and 3 for Reynolds numbers ranging from 10,000 to 100,000.",
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Establishing a methodology for resolving convective heat transfer from complex geometries. / Ostanek, Jason K.; Prausa, J.; Van Suetendael, A.; Thole, Karen A.

In: Journal of Turbomachinery, Vol. 132, No. 3, 031014, 01.07.2010.

Research output: Contribution to journalArticle

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