This paper presents an experimental study of the effect of unsteady blade row interaction on the migration of hot streaks in an axial turbine. The hot streaks can cause localized hot spots on the blade surfaces in a high-pressure turbine, leading to high heat loads and potentially catastrophic failure of the blades. An improved understanding of the effect of unsteady blade row interaction on an inlet temperature distortion is of crucial importance. The impact of hot streaks on the aerodynamic performance of a turbine stage is also not well understood. In the current experiment, the influence of hot streaks on a highly loaded 1.5-stage unshrouded model axial turbine is studied. A hot streak generator has been developed specifically for this project to introduce hot streaks that match the dimensional parameters of real engines. The temperature profile, spanwise position, circumferential position, and cross-section shape of the hot streak can be independently varied. The recently developed ETH Zurich two-sensor high temperature (260 °C) fast response aerodynamic probe (FRAP) technique and the fast response entropy. Probe (FENT) systems are used in this experimental campaign. Time resolved measurements of the unsteady pressure, temperature, and entropy are made at the NGV inlet and between the rotor and stator blade rows. From the nozzle guide vane inlet to outlet the measurements show a reduction in the maximum relative entropy difference between the free stream and the hot spot of 30% for the highest temperature gases in the core of the hot streak, indicating a region of heat loss. Time resolved flow field measurements at the rotor exit based on both measurement methods showed the hot gases traveling towards the hub and tip casing on the blade pressure side and interacting with secondary flows such as the hub passage vortex.

References

References
1.
Munk
,
M.
, and
Prim
,
R. C.
, 1947, “
On the Multiplicity of Steady Gas Flows Having the Same Streamline Pattern
,”
Proc. Nat. Acad. Sci. U.S.A.
,
33
(
1
), pp.
137
141
.
2.
Hermanson
,
K.
, and
Thole
,
K. A.
, 1999, “
Effect of Inlet Profiles on Endwall Secondary Flows
,”
J. Propul. Power
,
16
(
2
), pp.
286
296
.
3.
Barringer
,
K. A.
,
Thole
,
M. P. J. C.
, and
Koch
,
P. J.
, 2009, “
Migration of Combustor Exit Profiles Through High Pressure Turbine Vanes
,”
ASME J. Turbomach.
,
131
(
2
), p.
021010
.
4.
T. Povey
,
K. S.
,
Chana
,
T. J.
, and
Hurrion
,
J.
, 2007, “
The Effect of Hot Streaks on HP Vane Surface and Endwall Heat Transfer: An Experimental and Numerical Study
,”
J. Propul. Power
,
129
(
1
), pp.
32
43
.
5.
Barringer
,
K.
, and
Polanka
,
M.
, 2009, “
An Experimental Study of Combustor Exit Profile Shapes on Endwall Heat Transfer in High Pressure Turbine Vanes
,”
ASME J. Turbomach.
,
131
(
2
), p.
021009
.
6.
Jenkins
,
K. V.
, and
Bogard
,
D. G.
, 2004, “
The Effects of High Mainstream Turbulence and Turbine Vane Film Cooling on the Dispersion of a Simulated Hot Streak
,”
ASME J. Turbomach.
,
126
(
1
), pp.
203
211
.
7.
Butler
,
T. L.
, and
Sharma
,
O.
, 1989, “
Redistribution of an Inlet Temperature Distortion in an Axial Flow Turbine Stage
,”
J. Propul. Power
,
5
(
1
), pp.
64
71
.
8.
Roback
,
R.
, 1993, “
Hot streaks and Phantom Cooling in a Turbine Rotor Passage: Part1—Separate Effects
,”
ASME J. Turbomach.
,
115
(
4
), pp.
657
666
.
9.
Dorney
,
R. D.
, and
Edwards
,
D. E.
, 1992, “
Unsteady Analysis of Hot Streak Migration in a Turbine Stage
,”
J. Propul. Power
,
8
(
2
), pp.
520
529
.
10.
Rai
,
M. M.
, and
Dring
,
G. P.
, 1990, “
Navier-Stokes Analysis of the Redistribution of Inlet Temperature Distortions in a Turbine
,”
J. Propul. Power
,
6
(
3
), pp.
276
282
.
11.
Kerrebrock
,
J. L.
, and
Mikolajczak
,
A. A.
, 1970, “
Intra-stator Transport of Rotor Wakes and Its Effect on Compressor Performance
,”
J. Fluid Mech.
,
92
(
1
), pp.
359
369
.
12.
Ong
,
J.
, and
Miller
,
R.
, 2008, “
Hot Streak Vane Coolant Migration in a Downstream Rotor
,”
Proceedings of ASME Turbo Expo 2008
, Vol.
6
, pp.
1749
1760
.
13.
Bai-Tao
,
J. L.
, and
Hong-De
,
J.
, 2009, “
Combined Unsteady Effects of Hot Streak and Trailing Edge Coolant Ejection in a Turbine Stage
,”
Proceedings of ASME Turbo Expo 2009: Power for Land, Sea and Air
.
14.
Basol
,
P.
,
Jenny
,
C. L. A. K.
, and
Abhari
,
R. S.
, 2010, “
Hot Streak Migration in a Turbine Stage: Effect of Mixing on Hot Streak Attenuation
,”
Proceedings of ASME Turbo Expo 2010
.
15.
Behr
,
T.
,
Kalfas
,
A.
, and
Abhari
,
R. S.
, 2007, “
Unsteady Flow Physics and Performance of a One-and-1/2 Stage Unshrouded High Work Turbine
,”
ASME J. Turbomach.
,
129
(
2
), pp.
348
359
.
16.
Kupferschmied
,
O.
,
Kopperl
,
W. P. G.
, and
Gyarmathy
,
G.
, 2000, “
Time Resolved Flow Measurements With Fast Aerodynamic Probes in Turbomachinery
,”
Meas. Sci. Technol.
,
11
, pp.
1036
1054
.
17.
Lenherr
,
A. K.
, and
Abhari
,
R. S.
, 2010, “
High Temperature Fast Response Aerodynamic Probe
,”
Proceedings of ASME Turbo Expo2010
.
18.
Mansour
,
N.
,
Chokani
,
A. K.
, and
Abhari
,
R. S.
, 2008, “
Unsteady Entropy Measurements in a High Speed Radial Compressor
,”
ASME J. Eng. Gas Turbines Power
,
130
(
2
), p.
021603
.
19.
Mansour
,
N.
,
Chokani
,
A. K.
, and
Abhari
,
R. S.
, 2008, “
Time-Resolved Entropy Measurements Using a Fast Response Entropy Probe
,”
Meas. Sci. Technol.
,
19
(
11
), p.
115401
.
20.
Shang
,
T.
, and
Epstein
,
A.
, 1997, “
Analysis of Hot Streak Effects on Turbine Rotor Heat Load
,”
ASME J. Turbomach.
,
119
(
1
), pp.
544
533
.
21.
Bai-Tao
,
J. L.
, and
Hong-De
,
J.
, 2009, “
Numerical Investigation on Unsteady Effects of Hot Streak on Flow and Heat Transfer in a Turbine Stage
,”
ASME J. Turbomach.
,
131
(3)
, p.
031015
.
22.
Rose
,
M. G.
, 2009,
Unsteady Flow in Axial Turbines
,
Universitaet Stuttgart
,
Stuttgart, Germany
.
23.
Porreca
,
M.
,
Hollenstein
,
A. I. K.
, and
Abhari
,
R. S.
, 2007, “
Turbulence Measurements and Analysis in a Multistage Axial Turbine
,”
J. Propul. Power
,
23
(
1
), pp.
227
234
.
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