Film cooling experiments were run at the high speed cascade wind tunnel of the University of the Federal Armed Forces Munich. The investigations were carried out with a linear cascade of highly loaded turbine blades. The main objectives of the tests were to assess the film cooling effectiveness and the heat transfer in zones with main flow separation. Therefore, the blades were designed to force the flow to detach on the pressure side shortly downstream of the leading edge and reattach at about half of the axial chord. In this zone, film cooling rows are placed among others for a reduction of the size of the separation bubble. The analyzed region on the blade is critical due to the high heat transfer present at the leading edge and at the reattachment line after the main flow separation. Film cooling can contribute to a reduction of the size of the separation bubble reducing aerodynamic losses, however, in general, it increases heat transfer due to turbulent mixing. The reduction of the size of the separation bubble might also be twofold, since it acts like a thermal insulator on the blade and reducing the size of the bubble might lead to a stronger heating of the blade. Film cooling should, therefore, take both into account: first, a proper protection of the surface and second, reducing aerodynamic losses, diminishing the extension of the main flow separation. While experimental results of the adiabatic film cooling effectiveness were shown in previous publications, the local heat transfer is analyzed in this paper. Emphasis is also placed upon analyzing, in detail, the flow separation process. Furthermore, the tests comprise the analysis of the effect of different outlet Mach and Reynolds numbers and film cooling. In part two of this paper, the overall film cooling effectiveness is addressed. Local heat transfer is still difficult to predict with modern numerical tools and this is especially true for complex flows with flow separation. Some numerical results with the Reynolds averaged Navier-Stokes (RANS) and large eddy simulation (LES) show the capability of a commercial solver in predicting the heat transfer.

References

References
1.
Lakshminarayana
,
B.
,
1996
,
Fluid Dynamics and Heat Transfer of Turbomachinery
,
John Wiley & Sons, Inc.
,
New York
.
2.
Boyle
,
R.
,
Ames
,
F. E.
, and
Giel
,
P.
,
2004
, “
Predictions for the Effects of Freestream Turbulence on Turbine Blade Heat Transfer
,”
Proceedings of the ASME Turbo Expo
2004
,
Paper No. GT2004–54332
.
3.
Dunn
,
M. G.
,
2001
, “
Convective Heat Transfer and Aerodynamics in Axial Flow Turbines
,”
ASME J. Turbomach.
,
123
,
pp.
637
686
.10.1115/1.1397776
4.
Janke
,
E.
and
Wolf
,
T.
, 2010, “
Aerothermal Research for Turbine Components—An Overview of the European AITEB-2 Project
,”
Proceedings of the ASME Turbo Expo
2010
,
Paper No. GT2010–23511
.
5.
Duchaine
,
F.
,
Corpron
,
A.
,
Pons
,
L.
,
Moreau
,
V.
,
Nicoud
,
F.
, and
Poinsot
,
T.
,
2009
, “
Development and Assessment of a Coupled Strategy for Conjugate Heat Transfer With Large Eddy Simulation. Application to a Cooled Turbine Blade
,”
Int. J. Heat Fluid Flow
,
30
,
pp.
1129
1141
.10.1016/j.ijheatfluidflow.2009.07.004
6.
Pacciani
,
R.
,
Rubechini
,
F.
,
Arnone
,
A.
, and
Lutum
,
E.
, 2010, “
Calculation of Steady and Periodic Unsteady Blade Surface Heat Transfer in Separated Transitional Flow
,”
Proceedings of the ASME Turbo Expo
2010
,
Paper No. GT2010–23275
.
7.
Haselbach
,
F.
and
Schiffer
,
H.
, 2004, “
Aerothermal Investigations on Turbine Endwalls and Blades
,”
Proceedings of the ASME Turbo Expo
2004
,
Paper No. GT2004–53078
.
8.
Gomes
,
R.
and
Niehuis
,
R.
,
2009
, “
Film Cooling Effectiveness Measurements on Highly Loaded Blades With Flow Separation
,”
Proceedings of the 8th European Conference on Turbomachinery, Fluid Dynamics and Thermodynamics (ETC)
,
Paper No. 237
.
9.
Gomes
,
R. A.
and
Niehuis
,
R.
,
2011
, “
Film Cooling Effectiveness Measurements With Periodic Unsteady Inflow on Highly Loaded Blades With Main Flow Separation
,”
ASME J, Turbomach.
,
133
,
p.
021019
.10.1115/1.4000568
10.
de la Calzada
,
P.
and
Alonso
,
A.
,
2003
, “
Numerical Investigation of Heat Transfer in Turbine Cascades With Separated Flows
,”
ASME J. Turbomach.
,
125
,
pp.
260
266
.10.1115/1.1556014
11.
Alonso
,
A.
and
de la Calzada
,
P.
,
2003
, “
Steady/Unsteady Numerical Simulation of Heat Transfer in Turbine Cascades With Separated Flows
,”
5th European Conference on Turbomachinery
,
Fluid Dynamics and Thermodynamics
.
12.
Wolff
,
S.
,
Homeier
,
L.
, and
Fottner
,
L.
,
2001
, “
Experimental Investigation of Heat Transfer in Separated Flow on a Highly Loaded LP Turbine Cascade
,”
Proceeding of the RTO/AVT Symposium and Specialists Meeting
.
13.
Sturm
,
W.
and
Fottner
,
L.
,
1985
, “
The High-Speed Cascade Wind-Tunnel of the German Armed Forces University Munich
,”
8th Symposium on Measuring Techniques for Transonic and Supersonic Flows in Cascades and Turbomachines
.
14.
Farina
,
D. J.
,
Hacker
,
J. M.
,
Moffat
,
R. J.
, and
Eaton
,
J. K.
,
1993
, “
Illuminant Invariant Calibration of Thermochromic Liquid Crystals
,”
Visualization of Heat Transfer Processes, ASME-HTD
,
New York
, Vol.
252
, pp.
1
11
.
15.
Behle
,
M.
,
Schulz
,
K.
,
Leiner
,
W.
, and
Fiebig
,
M.
,
1996
, “
Color-Based Image Processing to Measure Local Temperature Distributions by Wide-Band Liquid Crystal Thermography
,”
App. Sci. Res.
,
56
,
pp.
113
143
.10.1007/BF02249377
16.
King
,
L. V.
,
1914
, “
On the Convection of Heat from Small Cylinders in a Stream of Fluid: Determination of the Convection Constants of Small Platinum Wires with Applications to Hot-Wire Anemometry
,”
Philos. Trans. R. Soc. London, Ser. A
,
214
,
pp.
373
432
.10.1098/rsta.1914.0023
17.
Wilcox
,
D.
,
1986
, “
Multiscale Model for Turbulent Flows
,”
AIAA 24th Aerospace Sciences Meeting
,
A. I. of Aeronautics and Astronautics, eds
.
18.
Menter
,
F.
,
1994
, “
Two-Equation Eddy-Viscosity Turbulence Models for Engineering Applications
,”
AIAA J.
,
32
(
8
),
pp.
1598
1605
.10.2514/3.12149
19.
Menter
,
F.
,
Langtry
,
R.
,
Likki
,
S.
,
Suzen
,
Y.
,
Huang
,
P.
, and
Völker
,
S.
,
2004
, “
A Correlation-Based Transition Model Using Local Variables—Part I: Model Formulation
,”
Proceedings of the ASME Turbo Expo 2004
,
Paper No. GT2004–53452
.
20.
Nicoud
,
F.
and
Ducros
,
F.
,
1999
, “
Subgrid-Scale Stress Modelling Based on the Square of the Velocity Gradient Tensor
,”
Flow, Turbul. Combust.
,
62
,
pp.
183
200
.10.1023/A:1009995426001
21.
Mayle
,
R. E.
,
1991
, “
The Role of Laminar-Turbulent Transition in Gas Turbine Engines
,”
ASME J. Turbomach.
,
113
,
pp.
509
537
.10.1115/1.2929110
22.
Homeier
,
L.
,
2004
, “
The Aerodynamic Effects of Film Cooling With Steady and Periodic Unsteady Inflow Conditions on HPT T120 With 2 Different Cooling Configurations
,”
Technical Report No. R-D1.5-P14/04, AITEB
.
23.
Gomes
,
R. A.
,
2010
, “
On Aerothermal Effects of Film Cooling on Turbine Blades with Flow Separation
,”
Ph.D. thesis
,
Universität der Bundeswehr München
,
Neubiberg
.
24.
Brear
,
M. J.
,
Hodson
,
H. P.
, and
Harvey
,
N. W.
,
2002
, “
Pressure Surface Separations in Low-Pressure Turbines—Part 1: Midspan Behavior
,”
ASME J. Turbomach.y
,
124
,
pp.
393
401
.10.1115/1.1450764
25.
Ladisch
,
H.
,
Schulz
,
A.
, and
Bauer
,
H.-J.
, 2009, “
Heat Transfer Measurements on a Turbine Airfoil With Pressure Side Separation
,”
Proceedings of the ASME Turbo Expo
2009
,
Paper No. GT2009–59904
.
26.
Giel
,
P. W.
,
Bunker
,
R. S.
,
Fossen
,
G. J. V.
, and
Boyle
,
R. J.
, 2000, “
Heat Transfer Measurements and Predictions on a Power Generation Gas Turbine Blade
,”
Proceedings of the ASME Turbo Expo
2000
,
Paper No. 2000–GT–0209
.
27.
Mick
,
W.
and
Mayle
,
R.
,
1988
, “
Stagnation Film Cooling and Heat Transfer, Including Its Effect Within the Hole Pattern
,”
ASME J. Turbomach.
,
110
,
pp.
66
72
.10.1115/1.3262169
You do not currently have access to this content.