Pin-fin arrays are commonly used as compact heat exchangers for cooling the trailing edge of gas turbine airfoils. While much research has been devoted to the heat transfer characteristics of various pin-fin configurations, little work has been done to investigate the flowfield in pin-fin arrays. Such information may allow for further optimization of pin-fin configurations. A new pin-fin facility at large scale has been constructed to allow optical access for the use of nonintrusive measurement techniques such as laser Doppler velocimetry and time-resolved, digital particle image velocimetry. Using these techniques, the flow through a single row of pin fins having a height-to-diameter ratio of 2 and span-to-diameter ratio of 2.5 was investigated. Results showed that the length of the wake region decreased with increasing Reynolds number. At higher Reynolds numbers, Kármán vortices developed closer to the pin fins than for single, infinitely long cylinders. Transverse fluctuations correlated well with endwall heat transfer indicating that the Kármán vortices play a key role in energy transport.

References

1.
Incropera
,
F. P.
, and
Dewitt
,
D. P.
, 2002,
Fundamentals of Heat and Mass Transfer
, 5th ed.,
John Wiley
,
New York
.
2.
Metzger
,
D. E.
, and
Haley
,
S. W.
, 1982, “
Heat Transfer Experiments and Flow Visualization for Arrays of Short Pin Fins
,” ASME Paper No. 82-GT-138.
3.
Simoneau
,
R. J.
, and
VanFossen
,
G. J.
, Jr.
, 1984, “
Effect of Location in an Array on Heat Transfer to a Short Cylinder in Crossflow
,”
ASME J. Heat Transfer
,
106
, pp.
42
48
.
4.
Ames
,
F. E.
,
Dvorak
,
L. A.
, and
Morrow
,
M. J.
, 2005, “
Turbulent Augmentation of Internal Convection Over Pins in Staggered-Pin Fin Arrays
,”
ASME J. Turbomach.
,
127
(
1
), pp.
183
190
.
5.
Metzger
,
D. E.
,
Berry
,
R. A.
, and
Bronson
,
J. P.
, 1982, “
Developing Heat Transfer in Rectangular Ducts With Staggered Arrays of Short Pin Fins
,”
ASME J. Heat Transfer
,
104
(
4
), pp.
700
706
.
6.
Ames
,
F. E.
,
Nordquist
,
C. A.
, and
Klennert
,
L. A.
, 2007, “
Endwall Heat Transfer Measurements in a Staggered Pin Fin Array With an Adiabatic Pin
,” ASME Paper No. GT2007-27432.
7.
Lyall
,
M. E.
,
Thrift
,
A. A.
,
Kohli
,
A.
, and
Thole
,
K. A.
, 2007, “
Heat Transfer From Low Aspect Ratio Pin Fins
,” ASME Paper No. GT2007-27431.
8.
Ozturk
,
N. A.
,
Akkoca
,
A.
, and
Sahin
,
B.
, 2008, “
PIV Measurements of Flow Past a Confined Cylinder
,”
Exp. Fluids
,
44
, pp.
1001
1014
.
9.
Brigham
,
B. A.
, and
VanFossen
,
G. J.
, 1984, “
Length to Diameter Ratio and Row Number Effects in Short Pin Fin Heat Transfer
,”
ASME J. Eng. Gas Turbines Power
,
106
(
1
), pp.
241
244
.
10.
Chyu
,
M. K.
,
Siw
,
S. C.
, and
Moon
,
H. K.
, 2009, “
Effects of Height-to-Diameter Ratio of Pin Element on Heat Transfer From Staggered Pin-Fin Arrays
,” ASME Paper No. GT2009-59814.
11.
Metzger
,
D. E.
,
Fan
,
C. S.
, and
Haley
,
S. W.
, 1984, “
Effects of Pin Shape and Array Orientation on Heat Transfer and Pressure Loss in Pin Fin Arrays
,”
ASME J. Eng. Gas Turbines Power
,
106
(
1
), pp.
252
257
.
12.
Uzol
,
O.
, and
Camci
,
C.
, 2005, “
Heat Transfer, Pressure Loss and Flow Field Measurements Downstream of Staggered Two-Row Circular and Elliptical Pin Fin Arrays
,”
ASME J. Heat Transfer
,
127
(
5
), pp.
458
471
.
13.
Raffel
,
M.
,
Willert
,
C.
,
Wereley
,
S.
, and
Kompenhans
,
J.
, 1998,
Particle Image Velocimetry: A Practicle Guide
,
Springer
,
New York
.
14.
Nogueira
,
J.
,
Lecuona
,
A.
, and
Rodriguez
,
P. A.
, 1997, “
Data Validation, False Vectors Correction and Derived Magnitudes Calculation on PIV Data
,”
Meas. Sci. Technol.
,
8
, pp.
1493
1501
.
15.
Moffat
,
R. J.
, 1988, “
Describing the Uncertainties in Experimental Results
,”
Exp. Thermal Fluid Sci.
,
1
(
1
), pp.
3
17
.
16.
Radomsky
,
R. W.
, and
Thole
,
K. A.
, 2000, “
High Free-Steam Turbulence Effects on Endwall Heat Transfer for a Gas Turbine Stator Vane
,”
ASME J. Turbomach.
,
122
, pp.
699
708
.
17.
Scarano
,
F.
, and
Riethmuller
,
M. L.
, 2000, “
Advances in Iterative Multigrid PIV Image Processing
,”
Exp. Fluids
,
29
, pp.
S051
S060
.
18.
Harder
,
K. J.
, and
Tiederman
,
W. G.
, 1991, “
Drag Reduction and Turbulent Structure in Two-Dimensional Channel Flows
,”
Phil. Trans. R. Soc. Ser. A
,
336
, pp.
19
34
.
19.
Praisner
,
T. J.
, and
Smith
,
C. R.
, 2006, “
The Dynamics of the Horseshoe Vortex and Associated Endwall Heat Transfer—Part I: Temporal Behavior
,”
ASME J. Turbomach.
,
128
(
4
), pp.
747
754
.
20.
Praisner
,
T. J.
, and
Smith
,
C. R.
, 2006, “
The Dynamics of the Horseshoe Vortex and Associated Endwall Heat Transfer—Part II: Time-Mean Results
,”
ASME J. Turbomach.
,
128
(
4
), pp.
755
762
.
21.
Devenport
,
W. J.
, and
Smith
,
R. L.
, 1990, “
Time-Dependent and Time-Averaged Turbulence Structure Near the Nose of a Wing-Body Junction
,”
J. Fluid Mech.
,
210
, pp.
23
55
.
22.
Zdravkovich
,
M. M.
, 1997,
Flow Around Circular Cylinders - Volume 1: Introduction
,
Oxford University Press
,
New York
.
23.
Ames
,
F. E.
, and
Dvorak
,
L. A.
, 2006, “
The Influence of Reynolds Number and Row Position on Surface Pressure Distributions in Staggered Pin Fin Arrays
,” ASME Paper No. GT2006-90170.
24.
Zdravkovich
,
M. M.
, 2003,
Flow Around Circular Cylinders - Volume 2: Applications
,
Oxford University Press
,
New York
.
25.
Norberg
,
C.
, 2003, “
Fluctuating Lift on a Circular Cylinder: Review and New Measurements
,”
J. Fluids Struct.
,
17
(
1
), pp.
57
96
.
26.
Norberg
,
C.
, and
Sunden
,
B.
, 1987, “
Turbulence and Reynolds Number Effects on the Flow and Fluid Forces on a Single Cylinder in Cross Flow
,”
J. Fluids Struct.
,
1
(
3
), pp.
337
357
.
27.
Ünal
,
U.
, and
Atlar
,
M.
, 2010, “
An Experimental Investigation into the Effect of Vortex Generators on the Near-Wake Flow of a Circular Cylinder
,”
Exp. Fluids
,
48
(
6
), pp.
1059
1079
.
28.
Ames
,
F. E.
, and
Dvorak
,
L. A.
, 2005, “
Turbulent Transport in Pin Fin Arrays—Experimental Data and Predictions
,” ASME Paper No. GT2005-68180.
29.
Colebrook
,
C. F.
, 1939, “
Turbulent Flow in Pipes, With Particular Reference to the Transition Region Between the Smooth and Rough Pipe Laws
,”
J. Inst. Civil Eng.
,
4
, pp.
133
156
.
30.
McAdams
,
W. H.
, 1942,
Heat Transmission
,
McGraw-Hill
,
New York
.
31.
Adrian
,
R. J.
,
Christensen
,
K. T.
, and
Liu
,
Z. C.
, 2000, “
Analysis and Interpretation of Instantaneous Turbulent Velocity Fields
,”
Exp. Fluids
,
29
(
3
), pp.
275
290
.
You do not currently have access to this content.