In a gas turbine engine the blade tips of the high-pressure turbine are exposed to high levels of convective heat transfer, because of the so-called tip-leakage phenomenon. The blade-lift distribution is known to control the flow distribution in the blade–tip gap. However, the interaction between upstream nozzle guide vanes and the rotor blades produces a time-varying flow field that induces varying flow conditions around the blade and within the tip gap. Extensive measurements of the unsteady blade-tip heat transfer have been made in an engine representative transonic turbine. These include measurements along the mean camber line of the blade tip, which have revealed significant variation in both time-mean and time-varying heat flux. The influences of potential interaction and the vane trailing edge have been observed. Numerical calculations of the turbine stage using a Reynolds-averaged-Navier-Stokes-based computational fluid dynamics code have also been conducted. In combination with the experimental results, these have enabled the time-varying flow field to be probed in the blade-relative frame of reference. This has allowed a deeper analysis of the unsteady heat-transfer data, and the quantification of the impact of vane potential field and vane trailing edge interaction on the tip-region flow and heat transfer. In particular, the separate effects of time-varying flow temperature and heat-transfer coefficient have been established.

References

References
1.
Bunker
,
R. S.
, 2001, “
A Review of Turbine Blade Tip Heat Transfer
Ann. N. Y. Acad. Sci.
934
, pp.
64
79
.
2.
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
,”
J. Turbomach.
,
122
, pp.
263
271
.
3.
Srinivasan
,
V.
, and
Goldstein
,
R. J.
, 2003, “
Effect of Endwall Motion on Blade Tip Heat Transfer
,”
J. Turbomach.
,
125
, pp.
267
273
.
4.
Moore
,
J.
, and
Elward
,
K. M.
, 1993, “
Shock Formation in Overexpanded Tip Leakage Flow
,”
J. Turbomach.
115
(
3
), pp.
392
399
.
5.
Didier
,
F.
,
Denos
,
R.
, and
Arts
,
T.
, 2002, “
Unsteady Rotor Heat Transfer in a Transonic Turbine Stage
,”
J. Turbomach.
,
124
, pp.
614
622
.
6.
Dunn
,
M. G.
, and
Haldeman
,
C. W.
, 2000, “
Time-Averaged Heat Flux for a Recessed Tip, Lip, and Platform of a Transonic Turbine Blade
,”
J. Turbomach.
,
122
(
4
), pp.
692
698
.
7.
Chana
,
K.
, and
Jones
,
T. V.
, 2003, “
An Investigation on Turbine Tip and Shroud Heat Transfer
,”
J. Turbomach.
,
125
(
3
), pp.
513
520
.
8.
Miller
,
R. J.
,
Moss
,
R. W.
,
Ainsworth
,
R. W.
, and
Harvey
,
N. W.
, 2003, “
Wake, Shock and Potential Field Interactions in a 1.5 Stage Turbine—Part I: Vane-Rotor and Rotor-Vane Interaction
,”
J. Turbomach.
,
125
(
1
), pp.
33
39
.
9.
Thorpe
,
S. J.
,
Yoshino
,
S.
,
Thomas
,
G. A.
,
Ainsworth
,
R. W.
,
Harvey
,
N. W.
, 2005, “
Blade-Tip Heat Transfer in a Transonic Turbine
,”
Proc. Inst. Mech. Eng., IMechE Conf.
,
219
(
6
), pp.
421
430
.
10.
Clark
,
J. P.
,
Polanka
,
M. D.
, and
Meininger
,
and M.
,
Praisner
T. J.
, 2006, “
Validation of Heat Predictions on the Outer Air Seal of a Transonic Turbine Blade
,”
J. Turbomach.
,
128
, p.
589
.
11.
Ainsworth
,
R. W.
,
Schultz
,
D. L.
,
Davies
,
M. R. D.
,
Forth
,
C. J. P.
,
Hilditch
,
M. A.
,
Oldfield
,
M. L. G.
, and
Sheard
,
A. G.
, 1988, “
A Transient Flow Facility for the Study of the Thermofluid-Dynamics of a Full Stage Turbine Under Engine Representative Flow Conditions
,” ASME Paper No. 88-GT-144.
12.
Ainsworth
,
R. W.
,
Allen
,
J. L.
,
Davies
,
M. R. D.
.
Doorly
,
J. E.
,
Forth
,
C. J. P.
,
Hilditch
,
M. A.
,
Oldfield
,
M. L. G.
, and
Sheard
A. G.
, 1989,
Developments in Instrumentation and Processing for Transient Heat Transfer Measurements in a Full-Stage Model Turbine
,
J. Turbomach.
111
, pp.
20
27
.
13.
Thorpe
,
S. J.
,
Yoshino
,
S.
,
Ainsworth
,
R. W.
,
Harvey
,
N. W.
, 2004, “
Improved Fast Response Heat Transfer Instrumentation for Short-Duration Wind Tunnels
,”
Meas. Sci. Technol.
15
, pp.
1897
1909
.
14.
Moinier
,
P.
, and
Giles
,
M. B.
, 1998, “
Preconditioned Euler and Navier-Stokes Calculations on Unstructured Grids
, 6th ICFD Conference on Numerical Methods for Fluid Dynamics, Oxford, UK.
15.
Miller
,
R. J.
,
Moss
,
R. W.
,
Ainsworth
,
R. W.
, and
Harvey
,
N. W.
, 2003, “
Wake, Shock and Potential Field Interactions in a 1.5 Stage Turbine—Part I: Vane-Vane Interaction and Discussion of Results
,”
J. Turbomach.
,
125
(
1
), pp.
40
47
.
16.
Denton
,
J. D.
, 1990, “
The Calculation of Three-Dimensional Viscous Flow Through Multistage Turbomachines
,” ASME Paper No. 90-GT-19.
17.
Atkins
,
N. R.
,
Ainsworth
,
R. W.
, and
Harvey
,
N. W.
, 2007, “
Aerodynamic Performance Measurement in a Fully Scaled Transient Turbine Test Facility
,” ASME Paper No. GT2007-27142.
18.
Dacles-Mariani
,
J.
,
Zilliac
,
G. G.
,
Chow
,
J. S.
, and
Bradshaw
,
P.
, 1995, “
Numerical/Experimental Study of a Wingtip Vortex in the Near Field
,”
AIAA J.
33
(
9
), pp.
1561
1568
.
19.
Vertsteeg
,
H. K.
, and
Malalasekera
,
W.
, 1985,
An Introduction to Computational Fluid Dynamics: The Finite Volume Method
,
Pearson
,
New York
.
20.
Dean
,
R. C.
, 1959, “
On the Necessity of Unsteady Flow in Fluid Machines
,”
J. Turbomach.
,
81
, pp.
24
28
.
21.
Johnson
,
A. B.
,
Rigby
,
M. J.
,
Oldfield
,
M. L. G.
,
Ainsworth
,
R. W.
, and
Oliver
,
M. J.
, 1988, “
Surface Heat Transfer Fluctuations on a Turbine Rotor Blade Due to Upstream Shock Wave Passing
,” ASME Paper No. 88-GT-172.
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