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contributor authorM. K. Chyu
contributor authorV. Natarajan
contributor authorY. C. Hsing
contributor authorT. I.-P. Shih
date accessioned2017-05-09T00:01:18Z
date available2017-05-09T00:01:18Z
date copyrightApril, 1999
date issued1999
identifier issn0889-504X
identifier otherJOTUEI-28669#257_1.pdf
identifier urihttp://yetl.yabesh.ir/yetl/handle/yetl/123035
description abstractShort pin-fin arrays are often used for cooling turbine airfoils, particularly near the trailing edge. An accurate heat transfer estimation from a pin-fin array should account for the total heat transfer over the entire wetted surface, which includes the pin surfaces and uncovered endwalls. One design question frequently raised is the actual magnitudes of heat transfer coefficients on both pins and endwalls. Results from earlier studies have led to different and often contradicting conclusions. This variation, in part, is caused by imperfect or unrealistic thermal boundary conditions prescribed in the individual test models. Either pins or endwalls, but generally not both, were heated in those previous studies. Using a mass transfer analogy based on the naphthalene sublimation technique, the present experiment is capable of revealing the individual heat transfer contributions from pins and endwalls with the entire wetted surface thermally active. The particular pin-fin geometry investigated, S/D = X/D = 2.5 and H/D = 1.0, is considered to be one of the optimal array arrangement for turbine airfoil cooling. Both inline and staggered arrays with the identical geometric parameters are studied for 5000 ≤ Re ≤ 25,000. The present results reveal that the general trends of the row-resolved heat transfer coefficients on either pins or endwalls are somewhat insensitive to the nature of thermal boundary conditions prescribed on the test surface. However, the actual magnitudes of heat transfer coefficients can be substantially different, due to variations in the flow bulk temperature. The present study also concludes that the pins have consistently 10 to 20 percent higher heat transfer coefficient than the endwalls. However, such a difference in heat transfer coefficient imposes very insignificant influence on the overall array-averaged heat transfer, since the wetted area of the uncovered endwalls is nearly four times greater than that of the pins.
publisherThe American Society of Mechanical Engineers (ASME)
titleHeat Transfer Contributions of Pins and Endwall in Pin-Fin Arrays: Effects of Thermal Boundary Condition Modeling
typeJournal Paper
journal volume121
journal issue2
journal titleJournal of Turbomachinery
identifier doi10.1115/1.2841309
journal fristpage257
journal lastpage263
identifier eissn1528-8900
keywordsHeat transfer
keywordsModeling
keywordsPins (Engineering)
keywordsThermal boundary layers
keywordsHeat transfer coefficients
keywordsAirfoils
keywordsTurbines
keywordsBoundary-value problems
keywordsCooling
keywordsFlow (Dynamics)
keywordsTemperature
keywordsMass transfer
keywordsGeometry AND Design
treeJournal of Turbomachinery:;1999:;volume( 121 ):;issue: 002
contenttypeFulltext


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