Most of the previous researches of inlet turbulence effects on blade tip have been carried out for low speed situations. Recent work has indicated that for a transonic turbine tip, turbulent diffusion tends to have a distinctively different impact on tip heat transfer than for its subsonic counterpart. It is hence of interest to examine how inlet turbulence flow conditioning would affect heat transfer characteristics for a transonic tip. The present work is aimed to identify and understand the effects of both inlet freestream turbulence and end wall boundary layer on a transonic turbine blade tip aerothermal performance. Spatially-resolved heat transfer data are obtained at aerodynamic conditions representative of a high-pressure turbine, using the transient infrared thermography technique with the Oxford High-Speed Linear Cascade research facility. With and without turbulence grids, the turbulence levels achieved are 7%–9% and 1%, respectively. On the blade tip surface, no apparent change in heat transfer was observed with high and low inlet turbulence intensity levels investigated. On the blade suction surface, however, substantially different local heat transfer distributions for the suction side near tip surface have been observed, indicating a strong local dependence of the local vortical flow structure on the freestream turbulence. These experimentally observed trends have also been confirmed by CFD examinations using the Rolls-Royce HYDRA. A further CFD analysis suggests that the level of inflow turbulence alters the balance between the passage vortex associated secondary flow and the over tip leakage (OTL) flow. Consequently, an enhanced inertia of near wall fluid at a higher inflow turbulence weakens the cross-passage flow. As such, the weaker passage vortex leads the tip leakage vortex to move further into the mid passage, with the less spanwise coverage on the suction surface, as consistently indicated by the heat transfer signature. Different inlet end wall boundary layer profiles are employed in the computational study with HYDRA. All CFD results indicate the inlet boundary layer thickness has little impact on the heat transfer over the tip surface as well as the pressure side near-tip surface. However, noticeable changes in heat transfer are observed for the suction side near-tip surface. Similar to the inlet turbulence effect, such changes can be attributed to the interaction between the passage vortex and the OTL flow.

References

References
1.
Goebel
,
S. G.
,
Abuaf
,
N.
,
Lovett
,
J. A.
, and
Lee
,
C. P.
,
1993
, “
Measurements of Combustor Velocity and Turbulence Profiles
,” ASME Paper No. 93-GT-228.
2.
Fossen
,
G. J. V.
, and
Bunker
,
R. S.
,
2001
, “
Augmentation of Stagnation Heat Transfer Due to Turbulence From a DLN Can Combustor
,”
ASME J. Turbomach.
,
123
, pp.
140
-
146
.10.1115/1.1330270
3.
Colban
,
W. F.
,
Lethander
,
A. T.
, and
Thole
,
K. A.
,
2003
, “
Combustor Turbine Interface Studies—Part 2: Flow and Thermal Field Measurements
,”
ASME J. Turbomach.
,
125
, pp.
203
209
.10.1115/1.1561812
4.
Radomsky
,
R. W.
, and
Thole
,
K. A.
,
2000
, “
Flowfield Measurements for a Highly Turbulent Flow in a Stator Vane Passage
,”
ASME J. Turbomach.
,
122
, pp.
255
262
.10.1115/1.555442
5.
Porreca
,
L.
,
Hollenstein
,
M.
,
Kalfas
,
A. I.
, and
Abhari
,
R. S.
,
2007
, “
Turbulence Measurements and Analysis in a Multistage Axial Turbine
,”
AIAA J. Propul. Power
,
23
, pp.
227
234
.10.2514/1.20022
6.
Choi
,
J.
,
Teng
,
S.
,
Han
,
J. C.
, and
Ladeinde
,
F.
,
2004
, “
Effect of Free-Stream Turbulence on Turbine Blade Heat Transfer and Pressure Coefficients in Low Reynolds Number Flows
,”
Int. J. Heat and Mass Transf.
,
47
, pp.
3441
3452
.10.1016/j.ijheatmasstransfer.2004.01.015
7.
Carullo
,
J. S.
,
Nasir
,
S.
,
Cress
,
R. D.
,
Ng
,
W. F.
,
Thole
,
K. A.
,
Zhang
,
L. J.
, and
Moon
,
H. K.
,
2011
, “
The Effects of Freestream Turbulence, Turbulence Length Scale, and Exit Reynolds Number on Turbine Blade Heat Transfer in a Transonic Cascade
,”
ASME J Turbomach.
,
133
, p.
011030
.10.1115/1.4001366
8.
Radomsky
,
R. W.
, and
Thole
,
K. A.
,
2000
, “
High Free-Steam Turbulence Effects on Endwall Heat Transfer for a Gas Turbine Stator Vane
,”
ASME J. Turbomach.
,
122
, pp.
699
708
.10.1115/1.1312807
9.
Ames
,
F. E.
,
Barbot
,
P. A.
, and
Wang
,
C.
,
2003
, “
Effects of Aero Derivative Combustor Turbulence on Endwall Heat Transfer Distributions Acquired in a Linear Vane Cascade
,”
ASME J. Turbomach.
,
125
, pp.
210
220
.10.1115/1.1559897
10.
Mehendale
,
A. B.
,
Han
,
J. C.
, and
Ou
,
S.
,
1991
, “
Influence of Mainstream Turbulence on Leading Edge Heat Transfer
,”
ASME J. Heat Transfer
,
113
, pp.
843
850
.10.1115/1.2911212
11.
Fiala
,
N. J.
,
Johnson
,
J. D.
, and
Ames
,
F. E.
,
2008
, “
Letterbox Trailing Edge Heat Transfer: Effects of Blowing Rate, Reynolds Number, and External Turbulence on Heat Transfer and Film Cooling Effectiveness
,”
ASME
Paper No. GT2008-50474.10.1115/GT2008-50474
12.
Azad
,
G. S.
,
Han
,
J. C.
,
Teng
,
S.
, and
Boyle
,
R.
,
2000
, “
Heat Transfer and Pressure Distributions on a Gas Turbine Blade Tip
,”
ASME J. Turbomach.
,
122
, pp.
717
724
.10.1115/1.1308567
13.
Azad
,
G. S.
,
Han
,
J. C.
, and
Boyle
,
R.
,
2000
, “
Heat Transfer and Pressure Distributions on the Squealer Tip of a Gas Turbine Blade
,”
ASME J. Turbomach.
,
122
, pp.
725
732
.10.1115/1.1311284
14.
Saxena
,
V.
,
Nasir
,
H.
, and
Ekkad
,
S. V.
,
2004
, “
Effect of Blade Tip Geometry on Tip Flow and Heat Transfer for a Blade in a Low-Speed Cascade
,”
ASME J. Turbomach.
,
126
, pp.
130
138
.10.1115/1.1643385
15.
Matsunuma
,
T.
,
2006
, “
Effects of Reynolds Number and Freestream Turbulence on Turbine Tip Clearance Flow
,”
ASME J. Turbomach.
,
128
, pp.
166
177
.10.1115/1.2103091
16.
Kwon
W. G.
, and
Lee
,
S. W.
,
2007
, “
Heat/Mass Transfer Characteristics in the Near-Tip Region on a Turbine Blade Surface Under Combustor-Level High Inlet Turbulence
,”
J. Mech. Sci. Technol.
,
21
, pp.
486
494
.10.1007/BF02916310
17.
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 1—Experimental Results
,”
ASME J. Turbomach.
,
122
, pp.
263
271
.10.1115/1.555443
18.
Wheeler
,
A. P. S.
,
Atkins
,
N. R.
, and
He
,
L.
,
2011
, “
Turbine Blade Tip Heat Transfer in Low Speed and High Speed Flows
,”
ASME J. Turbomach.
,
133
, p.
041025
.10.1115/1.4002424
19.
Zhang
,
Q.
,
O'Dowd
,
D.
,
He
,
L.
,
Wheeler
,
A. P. S.
,
Ligrani
,
P. M.
, and
Cheong
,
B. C. Y.
,
2011
, “
Over-Tip Shock Wave Structure and Its Impact on Turbine Blade Tip Heat Transfer
,”
ASME J. Turbomach.
,
133
, p.
041001
.10.1115/1.4002949
20.
Zhang
,
Q.
,
O'Dowd
,
D.
,
He
,
L.
,
Oldfield
,
M.
, and
Ligrani
,
P. M.
,
2011
, “
Transonic Turbine Blade Tip Aerothermal Performance With Different Tip Gaps—Part I: Tip Heat Transfer
,”
ASME J. Turbomach.
,
133
, p.
041027
.10.1115/1.4003063
21.
Zhang
,
Q.
, and
He
,
L.
,
2011
, “
Over-Tip Choking and Its Implications on Turbine Blade-Tip Aerodynamic Performance
,”
AIAA J. Propul. Power
,
27
, pp.
1008
1014
.10.2514/1.B34112
22.
O'Dowd
,
D.
,
Zhang
,
Q.
,
He
,
L.
,
Oldfield
,
M.
,
Ligrani
,
P. M.
,
Cheong
,
B. Y.
, and
Tibbott
,
I.
,
2011
, “
Aerothermal Performance of a Winglet Tip at Engine Representative Mach and Reynolds Numbers
,”
ASME J. Turbomach.
,
133
, p.
041026
.10.1115/1.4003055
23.
Gillespie
,
D. R. H.
,
Wang
,
Z.
, and
Ireland
,
P. T.
,
1995
, “
Heating Element
,” British Patent Application PCT/GB96/2017.
24.
O'Dowd
,
D.
,
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
, p.
021028
.10.1115/1.4001236
25.
Oldfield
,
M. L. G.
,
2008
, “
Impulse Response Processing of Transient Heat Transfer Gauge Signals
,”
ASME J. Turbomach.
,
130
(
2
), p.
021023
.10.1115/1.2752188
26.
Kline
,
S. J.
, and
McClintock
,
F. A.
,
1953
, “
Describing Uncertainties in Single-Sample Experiments
,”
ASME Mech. Eng.
,
75
, pp.
3
8
.
27.
Moffat
,
R. J.
,
1988
, “
Describing the Uncertainties in Experimental Results
,”
Exp. Thermal Fluid Sci.
,
1
, pp.
3
-
17
.10.1016/0894-1777(88)90043-X
28.
Coleman
,
H. W.
, and
Steele
,
W. G.
,
1989
,
Experimentation and Uncertainty Analysis for Engineers
,
John Wiley & Sons
,
New York
.
You do not currently have access to this content.