Recent studies have demonstrated that the aerothermal characteristics of turbine rotor blade tip under a transonic condition are qualitatively different from those under a low-speed subsonic condition. The cooling injection adds further complexity to the over-tip-leakage (OTL) transonic flow behavior and aerothermal performance, particularly for commonly studied shroudless tip configurations such as a squealer tip. However there has been no published experimental study of a cooled transonic squealer. The present study investigates the effect of cooling injection on a transonic squealer through a closely combined experimental and CFD effort. Part I of this two-part paper presents the first of the kind tip cooling experimental data obtained in a transonic linear cascade environment (exit Mach number 0.95). Transient thermal measurements are carried out for an uncooled squealer tip and six cooling configurations with different locations and numbers of discrete holes. High-resolution distributions of heat transfer coefficient and cooling effectiveness are obtained. ansysFluent is employed to perform numerical simulations for all the experimental cases. The mesh and turbulence modeling dependence is first evaluated before further computational studies are carried out. Both the experimental and computational results consistently illustrate strong interactions between the OTL flow and cooling injection. When the cooling injection (even with a relatively small amount) is introduced, distinctive series of stripes in surface heat transfer coefficient are observed with an opposite trend in the chordwise variations on the squealer cavity floor and on the suction surface rim. Both experimental and CFD results have also consistently shown interesting signatures of the strong OTL flow–cooling interactions in terms of the net heat flux reduction distribution in areas seemingly unreachable by the coolant. Further examinations and analyses of the related flow physics and underlining vortical flow structures will be presented in Part II.

References

References
1.
Bunker
,
R. S.
,
2001
, “
A Review of Turbine Blade Tip Heat Transfer
,”
Ann. N. Y. Acad. Sci.
,
934
(
1
), pp.
64
79
.
2.
Mayle
,
R.
, and
Metzger
,
D.
,
1982
, “
Heat Transfer at the Tip of an Unshrouded Turbine Blade
,”
7th International Conference on Heat Transfer
, Vol.
3
, pp.
87
92
.http://adsabs.harvard.edu/abs/1982hetr....3...87M
3.
Bunker
,
R. S.
,
Bailey
,
J. C.
, and
Ameri
,
A. A.
,
2000
, “
Heat Transfer and Flow on the First-Stage Blade Tip of a Power Generation Gas Turbine—Part I: Experimental Results
,”
ASME J. Turbomach.
,
122
(
2
), pp.
263
271
.
4.
Ameri
,
A. A.
, and
Bunker
,
R.
,
2000
, “
Heat Transfer and Flow on the First-Stage Blade Tip of a Power Generation Gas Turbine—Part II: Simulation Results
,”
ASME J. Turbomach.
,
122
(
2
), pp.
272
277
.
5.
Newton
,
P.
,
Lock
,
G.
,
Krishnababu
,
S.
,
Hodson
,
H.
,
Dawes
,
W.
,
Hannis
,
J.
, and
Whitney
,
C.
,
2006
, “
Heat Transfer and Aerodynamics of Turbine Blade Tips in a Linear Cascade
,”
ASME J. Turbomach.
,
128
(
2
), pp.
300
309
.
6.
Krishnababu
,
S.
,
Newton
,
P.
,
Dawes
,
W.
,
Lock
,
G. D.
,
Hodson
,
H.
,
Hannis
,
J.
, and
Whitney
,
C.
,
2009
, “
Aerothermal Investigations of Tip Leakage Flow in Axial Flow Turbines—Part I: Effect of Tip Geometry and Tip Clearance Gap
,”
ASME J. Turbomach.
,
131
(
1
), p.
011006
.
7.
Metzger
,
D.
,
Bunker
,
R.
, and
Chyu
,
M.
,
1989
, “
Cavity Heat Transfer on a Transverse Grooved Wall in a Narrow Flow Channel
,”
ASME J. Heat Transfer
,
111
(
1
), pp.
73
79
.
8.
Chyu
,
M.
,
Moon
,
H.
, and
Metzger
,
D.
,
1989
, “
Heat Transfer in the Tip Region of Grooved Turbine Blades
,”
ASME J. Turbomach.
,
111
(
2
), pp.
131
138
.
9.
Bunker
,
R. S.
, and
Bailey
,
J. C.
,
2001
, “
Effect of Squealer Cavity Depth and Oxidation on Turbine Blade Tip Heat Transfer
,”
ASME
Paper No. GT2000-0155.
10.
Azad
,
G. S.
,
Han
,
J.-C.
, and
Boyle
,
R. J.
,
2000
, “
Heat Transfer and Flow on the Squealer Tip of a Gas Turbine Blade
,”
ASME J. Turbomach.
,
122
(
4
), pp.
725
732
.
11.
Azad
,
G. S.
,
Han
,
J.-C.
,
Bunker
,
R. S.
, and
Lee
,
C. P.
,
2002
, “
Effect of Squealer Geometry Arrangement on a Gas Turbine Blade Tip Heat Transfer
,”
ASME J. Heat Transfer
,
124
(
3
), pp.
452
459
.
12.
Kwak
,
J. S.
,
Ahn
,
J.
,
Han
,
J. C.
,
Lee
,
C. P.
,
Bunker
,
R. S.
,
Boyle
,
R.
, and
Gaugler
,
R.
,
2003
, “
Heat Transfer Coefficients on the Squealer Tip and Near-Tip Regions of a Gas Turbine Blade With Single or Double Squealer
,”
ASME J. Turbomach.
,
125
(
4
), pp.
778
787
.
13.
Zhou
,
C.
, and
Hodson
,
H.
,
2012
, “
Squealer Geometry Effects on Aerothermal Performance of Tip-Leakage Flow of Cavity Tips
,”
J. Propul. Power
,
28
(
3
), pp.
556
567
.
14.
Bunker
,
R. S.
,
2006
, “
Axial Turbine Blade Tips: Function, Design, and Durability
,”
J. Propul. Power
,
22
(
2
), pp.
271
285
.
15.
Kwak
,
J. S.
, and
Han
,
J. C.
,
2003
, “
Heat Transfer Coefficients and Film-Cooling Effectiveness on a Gas Turbine Blade Tip
,”
ASME J. Heat Transfer
,
125
(
3
), pp.
494
502
.
16.
Christophel
,
J. R.
, and
Thole
,
K. A.
,
2005
, “
Cooling the Tip of a Turbine Blade Using Pressure Side Holes—Part I: Adiabatic Effectiveness Measurements
,”
ASME J. Turbomach.
,
127
(
2
), pp.
270
277
.
17.
Christophel
,
J. R.
,
Thole
,
K. A.
, and
Cunha
,
F. J.
,
2005
, “
Cooling the Tip of a Turbine Blade Using Pressure Side Holes—Part II: Heat Transfer Measurements
,”
ASME J. Turbomach.
,
127
(
2
), pp.
278
286
.
18.
Newton
,
P.
,
Lock
,
G. D.
,
Krishnababu
,
S.
,
Hodson
,
H.
,
Dawes
,
W.
,
Hannis
,
J.
, and
Whitney
,
C.
,
2009
, “
Aerothermal Investigations of Tip Leakage Flow in Axial Flow Turbines—Part III: Tip Cooling
,”
ASME J. Turbomach.
,
131
(
1
), p.
011008
.
19.
Kwak
,
J. S.
, and
Han
,
J. C.
,
2003
, “
Heat Transfer Coefficients and Film Cooling Effectiveness on the Squealer Tip of a Gas Turbine Blade
,”
ASME J. Turbomach.
,
125
(
4
), pp.
648
657
.
20.
Ahn
,
J.
,
Mhetras
,
S.
, and
Han
,
J.-C.
,
2005
, “
Film-Cooling Effectiveness on a Gas Turbine Blade Tip Using Pressure-Sensitive Paint
,”
ASME J. Heat Transfer
,
127
(
5
), pp.
521
530
.
21.
Mhetras
,
S.
,
Narzary
,
D.
,
Gao
,
Z.
, and
Han
,
J.-C.
,
2008
, “
Effect of a Cutback Squealer and Cavity Depth on Film-Cooling Effectiveness on a Gas Turbine Blade Tip
,”
ASME J. Turbomach.
,
130
(
2
), p.
021002
.
22.
Naik
,
S.
,
Georgakis
,
C.
,
Hofer
,
T.
, and
Lengani
,
D.
,
2012
, “
Heat Transfer and Film Cooling of Blade Tips and Endwalls
,”
ASME J. Turbomach.
,
134
(
4
), p.
041004
.
23.
Wheeler
,
A. P.
,
Atkins
,
N. R.
, and
He
,
L.
,
2011
, “
Turbine Blade Tip Heat Transfer in Low Speed and High Speed Flows
,”
ASME J. Turbomach.
,
133
(
4
), p.
041025
.
24.
Zhang
,
Q.
,
He
,
L.
,
Wheeler
,
A.
,
Ligrani
,
P.
, and
Cheong
,
B.
,
2011
, “
Overtip Shock Wave Structure and Its Impact on Turbine Blade Tip Heat Transfer
,”
ASME J. Turbomach.
,
133
(
4
), p.
041001
.
25.
Zhang
,
Q.
,
O'Dowd
,
D.
,
He
,
L.
,
Oldfield
,
M.
, and
Ligrani
,
P.
,
2011
, “
Transonic Turbine Blade Tip Aerothermal Performance With Different Tip Gaps—Part I: Tip Heat Transfer
,”
ASME J. Turbomach.
,
133
(
4
), p.
041027
.
26.
Zhang
,
Q.
, and
He
,
L.
,
2011
, “
Overtip Choking and Its Implications on Turbine Blade-Tip Aerodynamic Performance
,”
J. Propul. Power
,
27
(
5
), pp.
1008
1014
.
27.
Shyam
,
V.
,
Ameri
,
A.
, and
Chen
,
J.-P.
,
2012
, “
Analysis of Unsteady Tip and Endwall Heat Transfer in a Highly Loaded Transonic Turbine Stage
,”
ASME J. Turbomach.
,
134
(
4
), p.
041022
.
28.
Zhang
,
Q.
, and
He
,
L.
,
2014
, “
Impact of Wall Temperature on Turbine Blade Tip Aerothermal Performance
,”
ASME J. Eng. Gas Turbines Power
,
136
(
5
), p.
052602
.
29.
O'Dowd
,
D.
,
Zhang
,
Q.
,
He
,
L.
,
Oldfield
,
M.
,
Ligrani
,
P.
,
Cheong
,
B.
, and
Tibbott
,
I.
,
2011
, “
Aerothermal Performance of a Winglet at Engine Representative Mach and Reynolds Numbers
,”
ASME J. Turbomach.
,
133
(
4
), p.
041026
.
30.
Anto
,
K.
,
Xue
,
S.
,
Ng
,
W.
,
Zhang
,
L.
, and
Moon
,
H.
,
2013
, “
Effects of Tip Clearance Gap and Exit Mach Number on Turbine Blade Tip and Near-Tip Heat Transfer
,”
ASME
Paper No. GT2013-94345.
31.
Dunn
,
M.
, and
Haldeman
,
C.
,
2000
, “
Time-Averaged Heat Flux for a Recessed Tip, Lip, and Platform of a Transonic Turbine Blade
,”
ASME J. Turbomach.
,
122
(
4
), pp.
692
698
.
32.
Key
,
N. L.
, and
Arts
,
T.
,
2006
, “
Comparison of Turbine Tip Leakage Flow for Flat Tip and Squealer Tip Geometries at High-Speed Conditions
,”
ASME J. Turbomach.
,
128
(
2
), pp.
213
220
.
33.
Virdi
,
A.
,
Zhang
,
Q.
,
He
,
L.
,
Li
,
H.
, and
Hunsley
,
R.
,
2015
, “
Aerothermal Performance of Shroudless Turbine Blade Tips With Relative Casing Movement Effects
,”
J. Propul. Power
,
31
(
2
), pp.
527
536
.
34.
O'Dowd
,
D.
,
Zhang
,
Q.
,
He
,
L.
,
Cheong
,
B.
, and
Tibbott
,
I.
,
2013
, “
Aerothermal Performance of a Cooled Winglet at Engine Representative Mach and Reynolds Numbers
,”
ASME J. Turbomach.
,
135
(
1
), p.
011041
.
35.
Wheeler
,
A. P.
, and
Saleh
,
Z.
,
2013
, “
Effect of Cooling Injection on Transonic Tip Flows
,”
J. Propul. Power
,
29
(
6
), pp.
1374
1381
.
36.
Wang
,
Z.
,
Zhang
,
Q.
,
Liu
,
Y.
, and
He
,
L.
,
2015
, “
Impact of Cooling Injection on the Transonic Over-Tip Leakage Flow and Squealer Aerothermal Design Optimization
,”
ASME J. Eng. Gas Turbines Power
,
137
(
6
), p.
062603
.
37.
Zhou
,
C.
,
2015
, “
Thermal Performance of Transonic Cooled Tips in a Turbine Cascade
,”
J. Propul. Power
,
31
(
5
), pp.
1
13
.
38.
Ma
,
H.
,
Zhang
,
Q.
,
He
,
L.
,
Wang
,
Z.
, and
Wang
,
L.
,
2016
, “
Cooling Injection Effect on a Transonic Squealer Tip—Part 2: Analysis of Aerothermal Interaction Physics
,”
ASME
Paper No. GT2016-57587.
39.
Zheng
,
R.
,
Li
,
M.
,
Wang
,
Z.
, and
Zhang
,
Q.
,
2015
, “
Control of Blow-Down Wind Tunnel Using Combined Extended and Nonlinear Predictive Filters
,”
ASME
Paper No. GT2015-42908.
40.
Xi
,
J.
,
Zhang
,
Q.
,
Li
,
M.
, and
Wang
,
Z.
,
2013
, “
Advanced Flow Control for Supersonic Blowdown Wind Tunnel Using Extended Kalman Filter
,”
ASME
Paper No. GT2013-95281.
41.
Ma
,
H.
,
Wang
,
Z.
,
Wang
,
L.
,
Zhang
,
Q.
,
Yang
,
Z.
, and
Bao
,
Y.
,
2015
, “
Ramp Heating in High-Speed Transient Thermal Measurement With Reduced Uncertainty
,”
ASME
Paper No. GT2015-43012.
42.
Evans
,
R.
,
Dawes
,
W.
, and
Zhang
,
Q.
,
2013
, “
Application of Design of Experiment to a Gas Turbine Cascade Test Cell
,”
ASME
Paper No. GT2013-94314.
43.
Chen
,
W.
,
2013
, “
Improvements on Conventional Transient Thermal Measurement on Turbine Blade
,” M.S. thesis, Shanghai Jiao Tong University, Shanghai, China.
44.
Mee
,
D.
,
Chiu
,
H.
, and
Ireland
,
P.
,
2002
, “
Techniques for Detailed Heat Transfer Measurements in Cold Supersonic Blowdown Tunnels Using Thermochromic Liquid Crystals
,”
Int. J. Heat Mass Transfer
,
45
(
16
), pp.
3287
3297
.
45.
Kays
,
W. M.
,
Crawford
,
M. E.
, and
Weigand
,
B.
,
2012
,
Convective Heat and Mass Transfer
,
McGraw-Hill
,
New York
.
46.
Oldfield
,
M. L. G.
,
2008
, “
Impulse Response Processing of Transient Heat Transfer Gauge Signals
,”
ASME J. Turbomach.
,
130
(
2
), pp.
1
9
.
47.
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
.
48.
Devore
,
J.
,
2011
,
Probability and Statistics for Engineering and the Sciences
,
Cengage Learning
,
Boston, MA
.
49.
Coleman
,
H. W.
, and
Steele
,
W. G.
,
2009
,
Experimentation, Validation, and Uncertainty Analysis for Engineers
,
Wiley
,
New York
.
50.
Sen
,
B.
,
Schmidt
,
D. L.
, and
Bogard
,
D. G.
,
1996
, “
Film Cooling With Compound Angle Holes: Heat Transfer
,”
ASME J. Turbomach.
,
118
(
4
), pp.
800
806
.
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