This paper describes the experimental investigations of film-cooling effectiveness on a highly loaded low-pressure turbine blade under steady and unsteady wake flow conditions. The cascade facility in Turbomachinery Performance and Flow Research Lab (TPFL) at the Texas A&M University was used to simulate the periodic flow condition inside gas turbine engines. Moving wakes, originated from upstream stator blades, are simulated inside the cascade facility by moving rods in front of the blades. The flow coefficient is maintained at 0.8 and the incoming wakes have a reduced frequency of 3.18. A total of 617 holes on the blade are distributed along 13 different rows. Six rows cover the suction side, six other rows cover the pressure side, and one last row feeds the leading edge. Each row has a twin row on the other side of the blade with exact same number of holes and arrangement (except for leading edge). They both are connected to the same cavity. Coolant is injected from either sides of the blade through cavities to form a uniform distribution along the span of the blade. Film-cooling effectiveness under periodic unsteady flow condition was studied using pressure-sensitive paint. Experiments were performed at Reynolds number of 150,000 and blowing ratio of one, based on equal mass flux distribution. Experimental investigations were performed to determine the effect of flow separation and pressure gradient on film-cooling effectiveness. Moreover, the effect of impinging wakes on the overall film coverage of blade surfaces was studied. It was found that heat transfer coefficient (HTC) and film-cooling effectiveness (FCE) in majority of regions behave in opposite ways. This can be justified from turbulence intensity and velocity fluctuation point of view. Also, unsteady wakes imposed on top of film injection have opposite effects on suction and pressure side of the blade. This is more clearly seen in region near leading edge.

References

1.
Nirmalan
,
N. V.
, and
Hylton
,
L. D.
,
1990
, “
An Experimental Study of Turbine Vane Heat Transfer With Leading Edge and Downstream Film Cooling
,”
ASME J. Turbomach
.,
112
(
3
), pp.
477
487
.
2.
El-Gabry
,
L. A.
,
Thurman
,
D. R.
,
Poinsatte
,
P. E.
, and
Heidmann
,
J. D.
,
2011
, “
Turbulence and Heat Transfer Measurements in an Inclined Large Scale Film Cooling Array—Part I: Velocity and Turbulence Measurements
,”
ASME
Paper No. GT2011-46491.
3.
Thurman
,
D. R.
,
El-Gabry
,
L. A.
,
Poinsatte
,
P. E.
, and
Heidmann
,
J. D.
,
2011
, “
Turbulence and Heat Transfer Measurements in an Inclined Large Scale Film Cooling Array—Part II: Temperature and Heat Transfer Measurements
,”
ASME
Paper No GT2011-46498.
4.
Womack
,
K. M.
,
Volino
,
R. J.
, and
Schultz
,
M. P.
,
2008
, “
Measurements in Film Cooling Flows With Periodic Wakes
,”
ASME J. Turbomach.
,
130
(
4
), p.
041008
.
5.
Coulthard
,
S. M.
,
Volino
,
R. J.
, and
Flack
,
K. A.
,
2007
, “
Effect of Jet Pulsing on Film Cooling—Part I: Effectiveness and Flow-Field Temperature Results
,”
ASME J. Turbomach.
,
129
(
2
), pp.
232
246
.
6.
Coulthard
,
S. M.
,
Volino
,
R. J.
, and
Flack
,
K. A.
,
2007
, “
Effect of Jet Pulsing on Film Cooling—Part II: Heat Transfer Results
,”
ASME J. Turbomach.
,
129
(
2
), pp.
247
257
.
7.
Womack
,
K. M.
,
Volino
,
R. J.
, and
Schultz
,
M. P.
,
2008
, “
Combined Effects of Wakes and Jet Pulsing on Film Cooling
,”
ASME J. Turbomach.
,
130
(
4
), p.
041010
.
8.
Abuaf
,
N.
,
Bunker
,
R.
, and
Lee
,
C. P.
,
1997
, “
Heat Transfer and Film Cooling Effectiveness in a Linear Airfoil Cascade
,”
ASME J. Turbomach.
,
119
(
2
), pp.
302
309
.
9.
Takeishi
,
K.
,
Aoki
,
S.
,
Sato
,
T.
, and
Tsukagoshi
,
K.
,
1992
, “
Film Cooling on a Gas Turbine Rotor Blade
,”
ASME J. Turbomach.
,
114
(
4
), pp.
828
834
.
10.
McQuilling
,
M.
,
Wolff
,
M.
,
Fonov
,
S.
,
Crafton
,
J.
, and
Sondergaard
,
R.
,
2008
, “
An Experimental Investigation of a Low-Pressure Turbine Blade Suction Surface Using a Shear and Stress Sensitive Film
,”
Exp. Fluids
,
44
(1), pp.
73
88
.
11.
Schobeiri
,
M. T.
,
Öztürk
,
B.
,
Kegalj
,
M.
, and
Bensing
,
D.
,
2008
, “
On the Physics of Heat Transfer and Aerodynamic Behavior of Separated Flow Along a Highly Loaded Low Pressure Turbine Blade Under Periodic Unsteady Wake Flow and Varying of Turbulence Intensity
,”
ASME J. Heat Transfer
,
130
(
5
), p.
051703
.
12.
Polanka
,
M.
,
Clark
,
J.
,
White
,
A.
,
Meininger
,
M.
, and
Praisner
,
T.
, “
Turbine Tip and Shroud Heat Transfer and Loading—Part B: Comparisons Between Prediction and Experiment Including Unsteady Effects
,”
ASME
Paper No. GT2003-38916.
13.
Abhari
,
R. S.
, and
Epstein
,
A. H.
,
1994
, “
An Experimental Study of Film Cooling in a Rotating Transonic Turbine
,”
ASME J. Turbomach.
,
116
(
1
), pp.
63
70
.
14.
Wittig
,
S.
,
Schulz
,
A.
,
Dullenkopf
,
K.
, and
Fairbank
,
J.
,
1988
, “
Effects of Free-Stream Turbulence and Wake Characteristics on the Heat Transfer Along a Cooled Gas Turbine Blade
,”
ASME
Paper No. 88-GT-179.
15.
Heidmann
,
J. D.
,
Lucci
,
B. L.
, and
Reshotko
,
E.
,
2001
, “
An Experimental Study of the Effect of Wake Passing on Turbine Blade Film Cooling
,”
ASME J. Turbomach.
,
123
(
2
), pp.
214
221
.
16.
Haas
,
W.
,
Rodi
,
W.
, and
Schonung
,
B.
,
1992
, “
The Influence of Density Difference Between Hot and Coolant Gas on Film Cooling by a Row of Holes: Predictions and Experiments
,”
ASME J. Turbomach.
,
114
(
4
), pp.
747
755
.
17.
Bons
,
J. P.
,
2010
, “
A Review of Surface Roughness Effects in Gas Turbines
,”
ASME J. Turbomach.
,
132
(
2
), p.
021004
.
18.
Ames
,
F. E.
,
1998
, “
Aspects of Vane Film Cooling With High Turbulence—Part I: Heat Transfer
,”
ASME J. Turbomach.
,
120
(
4
), pp.
768
776
.
19.
Ames
,
F. E.
,
1998
, “
Aspects of Vane Film Cooling With High Turbulence—Part II: Adiabatic Effectiveness
,”
ASME J. Turbomach.
,
120
(
4
), pp.
777
784
.
20.
Dittmar
,
J.
,
Schulz
,
A.
, and
Wittig
,
S.
, “
Assessment of Various Film Cooling Configurations Including Shaped and Compound Angle Holes Based on Large Scale Experiments
,”
ASME
Paper No. GT2002-30176.
21.
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
(
2
), p.
021019
.
22.
Schobeiri
,
M. T.
,
Öztürk
,
B.
, and
Ashpis
,
D. E.
,
2005
, “
On the Physics of Flow Separation Along a Low Pressure Turbine Blade Under Unsteady Flow Conditions
,”
ASME J. Fluids Eng.
,
127
(
3
), pp.
503
513
.
23.
Öztürk
,
B.
, and
Schobeiri
,
M.
,
2007
, “
Effect of Turbulence Intensity and Periodic Unsteady Wake Flow Condition on Boundary Layer Development, Separation, and Reattachment Along the Suction Surface of a Low-Pressure Turbine Blade
,”
ASME J. Fluids Eng.
,
129
(
6
), pp.
747
763
.
24.
Schobeiri
,
M. T.
,
2014
, “
The Ultra-High Efficiency Gas Turbine (UHEGT) with Stator Internal Combustion
,” U.S. Patent No. 20160069261.
25.
Schobeiri
,
M. T.
, and
Ghoreyshi
,
S. M.
,
2016
, “
The Ultrahigh Efficiency Gas Turbine Engine With Stator Internal Combustion
,”
ASME J. Eng. Gas Turbines Power
,
138
(2), p.
021506
.
26.
Nomeli
,
M. A.
,
Tilton
,
N.
, and
Riaz
,
A.
,
2014
, “
A New Model for the Density of Saturated Solutions of CO2–H2O–NaCl in Saline Aquifers
,”
Int. J. Greenhouse Gas Control
,
31
, pp.
192
204
.
27.
Schobeiri
,
M. T.
, and
Nikparto
,
A.
,
2014
, “
A Comparative Numerical Study of Aerodynamics and Heat Transfer on Transitional Flow Around a Highly Loaded Turbine Blade With Flow Separation Using RANS, URANS and LES
,”
ASME
Paper No. GT2014-25828.
28.
Schobeiri
,
M. T.
, and
Pappu
,
K.
,
1997
, “
Experimental Study on the Effect of Unsteadiness on Boundary Layer Development on a Linear Turbine Cascade
,”
Exp. Fluids
,
23
(
4
), pp.
306
316
.
29.
Schobeiri
,
M. T.
,
Pappu
,
K.
, and
Wright
,
L.
,
1995
, “
Experimental Study of the Unsteady Boundary Layer Behavior on a Turbine Cascade
,”
ASME
Paper No. 95-GT-435.
30.
Schobeiri
,
M. T.
,
John
,
J.
, and
Pappu
,
K.
,
1994
, “
Development of Two-Dimensional Wakes Within Curved Channels: Theoretical Framework and Experimental Investigation
,”
ASME J. Turbomach.
,
118
(3), pp. 506–518.
31.
Schobeiri
,
M. T.
,
2013
,
Applied Fluid Mechanics for Engineers
,
McGraw-Hill
, New York.
32.
Schobeiri
,
M. T.
, and
Ozturk
,
B.
,
2004
, “
Experimental Study of the Effect of Periodic Unsteady Wake Flow on Boundary Layer Development, Separation, and Re-Attachment Along the Surface of a Low Pressure Turbine Blade
,”
ASME
Paper No. GT2004-53929.
33.
Schobeiri
,
M. T.
, and
Chakka
,
P.
,
2002
, “
Prediction of Turbine Blade Heat Transfer and Aerodynamics Using a New Unsteady Boundary Layer Transition Model
,”
Int. J. Heat Mass Transfer
,
45
(
4
), pp.
815
829
.
34.
Schobeiri
,
M. T.
, and
Özturk
,
B.
,
2004
, “
Turbulence Development and Decay Upstream of the LPT-Cascade
,” NASA GRC LPT-Project Progress Report, Report No. 32525-61640 ME.
35.
Wright
,
L.
, and
Schobeiri
,
M. T.
,
1999
, “
The Effect of Periodic Unsteady Flow on Aerodynamics and Heat Transfer on a Curved Surface
,”
ASME J. Heat Transfer
,
121
(
1
), pp.
22
33
.
36.
Schobeiri
,
M. T.
,
Öztürk
,
B.
, and
Ashpis
,
D. E.
,
2005
, “
Effect of Reynolds Number and Periodic Unsteady Wake Flow Condition on Boundary Layer Development, Separation, and Intermittency Behavior Along the Suction Surface of a Low Pressure Turbine Blade
,”
ASME J. Turbomach.
,
129
(1), pp.
92
107
.
37.
Ekkad
,
S. V.
, and
Han
,
J.-C.
,
2000
, “
A Transient Liquid Crystal Thermography Technique for Gas Turbine Heat Transfer Measurements
,”
Meas. Sci. Technol.
,
11
(
7
), p.
957
.
38.
Gritsch
,
M.
,
Schulz
,
A.
, and
Wittig
,
S.
,
1997
, “
Adiabatic Wall Effectiveness Measurements of Film-Cooling Holes With Expanded Exits
,”
ASME
Paper No. 97-GT-164.
39.
Wagner
,
G.
,
Vogel
,
G.
,
Chanteloup
,
D.
, and
Bölcs
,
A.
,
2002
, “
Pressure Sensitive Paint (PSP) and Transient Liquid Crystal Technique (TLC) for Measurements of Film Cooling Performances
,”
16th Bi-Annual Symposium on Measuring Techniques in Transonic and Supersonic Flow in Cascades and Turbomachines
, Paper No. LTT-CONF-2002-009.
40.
Coleman
,
H. W.
, and
Steele
,
W. G.
,
2009
,
Experimentation, Validation, and Uncertainty Analysis for Engineers
,
Wiley
, Hoboken, NJ.
41.
Pfeil
,
H.
,
Herbst
,
R.
, and
Schröder
,
T.
,
1982
, “
Investigation of the Laminar-Turbulent Transition of Boundary Layers Disturbed by Wakes
,”
ASME
Paper No. 82-GT-124.
42.
Sharma
,
O. P.
, and
Butler
,
T. L.
,
1986
, “
Predictions of Endwall Losses and Secondary Flows in Axial Flow Turbine Cascades
,”
ASME
Paper No. 86-GT-228.
43.
Wang
,
J.
,
Sundén
,
B.
,
Zeng
,
M.
, and
Wang
,
Q.-W.
,
2012
, “
Effect of Upstream Wake on Passage Flow and Tip Film Cooling Characteristics
,”
ASME
Paper No. GT2012-68562.
44.
Funazaki
,
K.
,
Yokota
,
M.
, and
Yamawaki
,
S.
,
1997
, “
Effect of Periodic Wake Passing on Film Effectiveness of Discrete Cooling Holes Around the Leading Edge of a Blunt Body
,”
ASME J. Turbomach.
,
119
(
2
), pp.
292
301
.
45.
Schwarz
,
S. G.
,
Goldstein
,
R. J.
, and
Eckert
,
E. R. G.
,
1991
, “
The Influence of Curvature on Film Cooling Performance
,”
ASME J. Turbomach.
,
113
(
3
), pp.
472
478
.
You do not currently have access to this content.