Pin fin arrays are most commonly used to promote convective cooling within the internal passages of gas turbine airfoils. Contributing to the heat transfer are the surfaces of the channel walls as well as the pin itself. Generally the pin fin cross section is circular; however, certain applications benefit from using other shapes such as oblong pin fins. The current study focuses on characterizing the heat transfer distribution on the surface of oblong pin fins with a particular focus on pin spacing effects. Comparisons were made with circular cylindrical pin fins, where both oblong and circular cylindrical pins had a height-to-diameter ratio of unity, with both streamwise and spanwise spacing varying between two and three diameters. To determine the effect of relative pin placement, measurements were taken in the first of a single row and in the third row of a multirow array. Results showed that area-averaged heat transfer on the pin surface was between 30 and 35% lower for oblong pins in comparison to cylindrical. While heat transfer on the circular cylindrical pin experienced one minimum prior to boundary layer separation, heat transfer on the oblong pin fins experienced two minimums, where one is located before the boundary layer transitions to a turbulent boundary layer and the other prior to separation at the trailing edge.

References

References
1.
Armstrong
,
J.
, and
Winstanley
D.
,
1988
, “
Review of Staggered Array Pin Fin Heat Transfer for Turbine Cooling Applications
,”
ASME J. Turbomach.
,
110
(1), pp.
94
103
.10.1115/1.3262173
2.
Metzger
,
D. E.
,
Shepard
,
W. B.
, and
Haley
S. W.
,
1986
, “
Row Resolved Heat Transfer Variations in Pin-Fin Arrays Including Effects of Non-Uniform Arrays and Flow Convergence
,”
ASME Paper No. 86-GT-132
.
3.
Vanfossen
G. J.
,
1982
, “
Heat-Transfer Coefficients for Staggered Arrays of Short Pin Fins
,”
J. Eng. Power
,
104
(
2
), pp.
268
274
.10.1115/1.3227275
4.
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
. 10.1115/1.3239541
5.
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 Transf.
,
106
(
1
), pp.
42
48
.10.1115/1.3246657
6.
Lyall
,
M. E.
,
Thrift
,
A. A.
,
Thole
,
K. A.
, and
Kohli
A.
,
2011
, “
Heat Transfer From Low Aspect Ratio Pin Fins
,”
ASME J. Turbomach.
,
133
(
1
), p.
011001
.10.1115/1.2812951
7.
Lawson
,
S. A.
,
Thrift
,
A. A.
,
Thole
,
K. A.
, and
Kohli
A.
,
2011
, “
Heat Transfer From Multiple Row Arrays of Low Aspect Ratio Pin Fins
,”
Int. J. Heat Mass Transf.
,
54
(
17–18
), pp.
4099
4109
.10.1016/j.ijheatmasstransfer.2011.04.001
8.
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. 10.1115/GT2009-59814
9.
Chyu
M. K.
,
1990
, “
Heat Transfer and Pressure Drop for Short Pin-Fin Arrays With Pin End Wall Fillet
,”
ASME J. Heat Transf.
,
112
(
4
), pp.
926
932
.10.1115/1.2910502
10.
Arora
,
S. C.
, and
Abdel-Messeh
W.
,
1990
, “
Characteristics of Partial Length Circular Pin Fins as Heat Transfer Augmentors for Airfoil Internal Cooling Passages
,”
ASME J. Turbomach.
,
112
(3), pp.
559
565
. 10.1115/1.2927694
11.
Busche
,
M. L.
,
Moualeu
,
L. P.
,
Chowdhury
,
N.
,
Tang
,
C.
, and
Ames
,
F. E.
,
2012
, “
Heat Transfer and Pressure Drop Measurements in High Solidity Pin Fin Cooling Arrays With Incremental Replenishment
,”
ASME
Paper No. GT2012-69289. 10.1115/GT2012-69289
12.
Chyu
,
M. K.
,
Hsing
,
Y. C.
, and
Natarajan
V.
,
1998
, “
Convective Heat Transfer of Cubic Fin Arrays in a Narrow Channel
,”
ASME J. Turbomach.
,
120
(
2
), pp.
362
367
.10.1115/1.2841414
13.
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 Transf.
,
127
(
5
), pp.
458
471
.10.1115/1.1860563
14.
Ling
,
J.
,
Yapa
,
S. D.
,
Benson
,
M. J.
,
Elkins
,
C. J.
, and
Eaton
,
J. K.
,
2012
, “
3D Velocity and Scalar Field Measurements of an Airfoil Trailing Edge With Slot Film Cooling: The Effect of an Internal Structure in the Slot
,”
ASME
Paper No. GT2012-68364. 10.1115/GT2012-68364
15.
Andreini
,
A.
,
Carcasci
,
C.
, and
Magi
,
A.
,
2004
, “
Heat Transfer Analysis of a Wedge Shaped Duct With Pin Fin and Pedestal Arrays: A Comparison Between Numerical and Experimental Results
,”
ASME
Paper No. GT2004-53319. 10.1115/GT2004-53319
16.
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 Turb. Power
,
106
(
1
), pp.
252
257
.10.1115/1.3239545
17.
Ames
,
F. E.
, and
Dvorak
L. A.
,
2005
, “
Turbulent Augmentation of Internal Convection Over Pins in Staggered Pin-Fin Arrays
,”
ASME J. Turbomach.
,
127
(
1
), pp.
183
191
.10.1115/1.1811090
18.
Ostanek
,
J. K.
, and
Thole
K. A.
,
2012
, “
Flowfield Measurements in a Single Row of Low Aspect Ratio Pin-Fins
,”
ASME J. Turbomach.
,
153
(
5
), p.
051034
.10.1115/1.4004755
19.
Ostanek
,
J. K.
,
2012
, “
Flowfield Interactions in Low Aspect Ratio Pin-Fin Arrays
,”
Ph.D. dissertation
,
Penn State University
,
University Park, PA
.
20.
Moffat
,
R. J.
,
1988
, “
Describing the Uncertainties in Experimental Results
,”
Experiment. Therm. Fluid Sci.
,
1
(
1
), pp.
3
17
.10.1016/0894-1777(88)90043-X
21.
Zdravkovich
,
M. M.
,
1997
,
Flow Around Circular Cylinders—Volume 1: Introduction
,
Oxford University Press
,
New York
.
22.
Ostanek
,
J. K.
, and
Thole
,
K. A.
,
2012
, “
Wake Development in Staggered Short Cylinder Arrays Within a Channel
,”
Experiments Fluids
,
53
(
3
), pp.
673
697
.10.1007/s00348-012-1313-5
You do not currently have access to this content.