In order to continue increasing the efficiency of gas turbines, a significant effort is being made to reduce losses induced by secondary flows in turbine stages. In addition to their impact on aerodynamic losses, these vortical structures are also the source of large heat transfer variations across the passage. A substantial reduction of the secondary flow losses can be achieved with a contoured endwall. However, a change in the vortical pattern can dramatically impact the thermal loads on the endwalls and lead to higher cooling requirements in those areas. This paper focuses on heat transfer measurements made in a passage with either flat or contoured endwalls. The experimental data are supplemented with numerical predictions of the heat transfer data. The measurements are carried out on an isothermal endwall equipped with symmetric airfoils. The paper presents measurements at M = 0.3, corresponding to a Reynolds number ReCax=4.6×105. An infrared camera is used to provide high-resolution surface temperature data on the endwall. The surface is equipped with an insulating layer (Kapton), allowing the calculation of heat flux through the endwall. The heat transfer quantities, namely the heat transfer coefficient and the adiabatic wall temperature, are then derived from a set of measurements at different isothermal plate temperatures. The numerical predictions clarify the link between the change in the heat transfer quantities and the changes in the flow field due to endwall contouring. Finally, numerically predicted heat transfer data are deduced from a set of adiabatic and diabatic simulations that are compared to the experimental data. The comparison focuses on the differences in the regions with endwall contouring, where a significant difference in the heat transfer coefficient between flat and contoured endwalls is measured but underpredicted numerically.

References

References
1.
Langston
,
L.
,
Nice
,
M.
, and
Hooper
,
R.
,
1977
, “
3-Dimensional Flow Within a Turbine Cascade Passage
,”
ASME J. Eng. Power
,
99
(
1
), pp.
21
28
.10.1115/1.3446247
2.
Blair
,
M.
,
1974
, “
An Experimental Study of Heat Transfer and Film Cooling on Large-Scale Turbine Endwalls
,”
ASME J. Heat Transfer
,
96
, pp.
524
529
.10.1115/1.3450239
3.
Graziani
,
R. A.
,
Blair
,
M. F.
,
Taylor
,
J. R.
, and
Mayle
,
R. E.
,
1980
, “
An Experimental Study of Endwall and Airfoil Surface Heat Transfer in a Large Scale Turbine Blade Cascade
,”
ASME J. Eng. Power
,
102
(
2
), pp.
257
267
.10.1115/1.3230246
4.
Han
,
S.
, and
Goldstein
,
R. J.
,
2007
, “
Heat Transfer Study in a Linear Turbine Cascade Using a Thermal Boundary Layer Measurement Technique
,”
ASME J. Heat Transfer
,
129
(
10
), pp.
1384
1394
.10.1115/1.2754972
5.
Brennan
,
G.
,
Harvey
,
N. W.
,
Rose
,
M. G.
,
Fomison
,
N.
, and
Taylor
,
M. D.
,
2003
, “
Improving the Efficiency of the Trent 500-hp Turbine Using Nonaxisymmetric End Walls—Part I: Turbine Design
,”
ASME J. Turbomach.
,
125
(
3
), pp.
497
504
.10.1115/1.1450766
6.
Ingram
,
G.
,
Gregory-Smith
,
D.
,
Rose
,
M.
,
Harvey
,
N.
, and
Brennan
,
G.
,
2002
, “
The Effect of End-Wall Profiling on Secondary Flow and Loss Development in a Turbine Cascade
,” ASME Conference Proceedings,
ASME
Paper No. GT2002-30339, pp.
135
145
.10.1115/GT2002-30339
7.
Schuepbach
,
P.
,
Abhari
,
R. S.
,
Rose
,
M. G.
, and
Gier
,
J.
,
2011
, “
Influence of Rim Seal Purge Flow on the Performance of an Endwall-Profiled Axial Turbine
,”
ASME J. Turbomach.
,
133
(
2
), p.
021011
.10.1115/1.4000578
8.
Germain
,
T.
,
Nagel
,
M.
,
Raab
,
I.
,
Schüpbach
,
P.
,
Abhari
,
R. S.
, and
Rose
,
M.
,
2010
, “
Improving Efficiency of a High Work Turbine Using Nonaxisymmetric Endwalls—Part I: Endwall Design and Performance
,”
ASME J. Turbomach.
,
132
(
2
), p.
021007
.10.1115/1.3106706
9.
Schuepbach
,
P.
,
Abhari
,
R. S.
,
Rose
,
M. G.
,
Germain
,
T.
,
Raab
,
I.
, and
Gier
,
J.
,
2010
, “
Improving Efficiency of a High Work Turbine Using Nonaxisymmetric Endwalls—Part II: Time-Resolved Flow Physics
,”
ASME J. Turbomach.
,
132
(
2
), p.
021008
.10.1115/1.3103926
10.
Lynch
,
S. P.
,
Sundaram
,
N.
,
Thole
,
K. A.
,
Kohli
,
A.
, and
Lehane
,
C.
,
2011
, “
Heat Transfer for a Turbine Blade With Nonaxisymmetric Endwall Contouring
,”
ASME J. Turbomach.
,
133
(
1
), p.
011019
.10.1115/1.4000542
11.
O'Dowd
,
D. O.
,
Zhang
,
Q.
,
He
,
L.
,
Ligrani
,
P. M.
, and
Friedrichs
,
S.
,
2011
, “
Comparison of Heat Transfer Measurement Techniques on a Transonic Turbine Blade Tip
,”
ASME J. Turbomach.
,
133
(
2
), p.
021028
.10.1115/1.4001236
12.
Giel
,
P. W.
,
Van Fossen
,
G.
,
Boyle
,
R.
,
Thurman
,
D.
, and
Civinskas
,
K.
,
1999
, “
Blade Heat Transfer Measurements and Predictions in a Transonic Turbine Cascade
,” NASA/TM Paper No. 209296.
13.
Carlomagno
,
G.
, and
Cardone
,
G.
,
2010
, “
Infrared Thermography for Convective Heat Transfer Measurements
,”
Exp. Fluids
,
49
, pp.
1187
1218
.10.1007/s00348-010-0912-2
14.
Lewis
,
D.
, and
Simpson
,
R.
,
1996
, “
An Experimental Investigation of Heat Transfer in Three-Dimensional and Separating Turbulent Boundary Layers
,” VPI, Blacksburg, VA, Technical Report No. VPI-AOE-229.
15.
Devenport
,
W.
, and
Simpson
,
R.
,
1990
, “
Time-Dependent and Time-Averaged Turbulence Structure Near the Nose of a Wing-Body Junction
,”
J. Fluid Mech.
,
210
, pp.
23
55
.10.1017/S0022112090001215
16.
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
.10.1115/1.2185677
17.
Hada
,
S.
,
Takeishi
,
K.
,
Oda
,
Y.
,
Mori
,
S.
, and
Nuta
,
Y.
,
2008
, “
The Effect of Leading Edge Diameter on the Horse Shoe Vortex and Endwall Heat Transfer
,”
ASME Conference Proceedings, Paper No. 43147
, pp.
813
823
.
18.
Bernsdorf
,
S.
,
2005
, “
Experimental Investigation of Film Cooling Flow Structure
,” Ph.D. thesis, Eidgenössische Technische Hochschule Zürich, Zurich.
19.
Laveau
,
B.
, and
Abhari
,
R. S.
,
2010
, “
Influence of Flow Structure on Shaped Hole Film Cooling Performance
,” ASME Conference Proceedings,
ASME
Paper No. GT2010-23032, pp.
1677
1689
.10.1115/GT2010-23032
20.
Gengenbach
,
J.
,
Kabelac
,
S.
, and
Koirala
,
L. R.
,
2005
, “
Measurement of Directional Spectral Emissivities of Microstructured Surfaces
,” Proceedings 17th European Conference on Thermophysical Properties (ECTP), Bratislava, Slovakia, September 5–8, ECTP Paper No. 183.
21.
Vidakovic
,
Z.
,
2007
, “
Estimating the Radiation Correction on Heat Transfer Measurements for a Film Cooling Experiment
,” Master's thesis, ETH Zurich, Switzerland.
22.
Baldauf
,
S.
,
Schulz
,
A.
, and
Wittig
,
S.
,
2001
, “
High Resolution Measurements of Local Effectiveness From Discrete Hole Film Cooling
,”
ASME J. Turbomach.
,
123
, pp.
758
765
.10.1115/1.1371778
23.
Moffat
,
R. J.
,
1988
, “
Describing the Uncertainties in Experimental Results
,”
Exp. Therm. Fluid Sci.
,
1
, pp.
3
17
.10.1016/0894-1777(88)90043-X
24.
Kline
,
S. J.
, and
McClintock
,
F. A.
,
1953
, “
Describing Uncertainties in Single-Sample Experiments
,”
Mech. Eng. (Am. Soc. Mech. Eng.)
,
75
, pp.
3
8
.
25.
Kays
,
W.
,
Crawford
,
M.
, and
Weigand
,
B.
,
2004
,
Convective Heat and Mass Transfer
,
McGraw-Hill
,
New York.
26.
Crawford
,
M. E.
,
2010
, Texstan Boundary Layer Code, www.texstan.com
27.
Simpson
,
R.
,
2001
, “
Junction Flows
,”
Annu. Rev. Fluid Mech.
,
33
, pp.
413
443
.10.1146/annurev.fluid.33.1.415
28.
Jeong
,
J.
, and
Hussain
,
F.
,
1995
, “
On the Identification of a Vortex
,”
J. Fluid Mech.
,
285
, pp.
69
94
.10.1017/S0022112095000462
You do not currently have access to this content.