The paper presents an experimental investigationof the effect of the trailing edge vortex shedding on the steady and unsteady trailing blade pressure distribution of a turbine blade at high subsonic Mach number M2,is=0.79 and high Reynolds number RE=2.8×106. The vortex formation and shedding process is visualized using a high-speed schlieren camera and a holographic interferometric density measuring technique. The blade is equipped with a rotatable trailing edge cylinder instrumented side-by-side with a pneumatic pressure tap and a fast response pressure sensor for detailed measurements of the trailing edge pressure distribution. The experiments demonstrate that contrary to the isobaric dead air region demonstrated at low subsonic Mach numbers the data reveal the existence of a highly nonuniform trailing edge pressure distribution with a strong pressure minimum at the center of the trailing edge. This finding is significant for the determination of the base pressure coefficient that is in general measured with a single pressure-sensing hole at the trailing edge center. The paper investigates further the effect of the vortex shedding on the blade rear suction side and discusses the superposition of unsteady effects emanating from the trailing edge and from the neighboring blade. The experimental data are a unique source for the validation of unsteady Navier-Stokes codes.

Issue Section:
Technical Papers
Keywords:
turbines, aerodynamics, subsonic flow, Mach number, external flows
Topics:
Blades, Flow (Dynamics), Mach number, Pressure, Suction, Boundary layers, Vortex shedding, Wakes
1.
Ubaldi, M., and Zunino, P., 1999, “An Experimental Study of the Unsteady Characteristics of the Turbulent Wake of a Turbine Blade,” 4th Int. Symp. Engineering Turbulence Modeling and Measurements, Ajaccio.
2.
Cicatelli
,
G.
, and
Sieverding
,
C. H.
,
1997
, “
The Effect of Vortex Shedding on the Unsteady Pressure Distribution around the Trailing Edge of a Turbine Blade
,”
ASME J. Turbomach.
,
119
(
4
), pp.
810
–
819
.
3.
Traupel, W., 1997, Thermische Turbomaschinen, Erster Band, Springer.
4.
Denton
,
J. D.
,
1993
, “
Loss Mechanisms in Turbomachines
,”
ASME J. Turbomach.
,
115
(
4
), pp.
621
–
656
.
5.
Sieverding
,
C. H.
,
Stanislas
,
M.
, and
Snoeck
,
J.
,
1980
, “
The Base Pressure Problem in Transonic Turbine Blades
,”
ASME J. Eng. Power
,
102
(
3
), pp.
711
–
718
.
6.
Xu
,
L.
, and
Denton
,
J. D.
,
1988
, “
The Base Pressure Loss of a Family of Four Turbine Blades
,”
ASME J. Turbomach.
,
110
(
1
), pp.
9
–
17
.
7.
Jouini, D. B. M., Sjolander, S. A., and Moustapha, S. H., 2000, “Aerodynamic Performance of a Transonic Turbine Cascade at Off-Design Conditions,” ASME Paper No. 2000-GT-0482
8.
Han
,
L. S.
, and
Cox
,
W. R.
,
1983
, “
A Visual Study of Turbine Blade Pressure Side Boundary Layer
,”
ASME J. Eng. Power
,
105
(
1
), pp.
47
–
52
.
9.
Lawaczeck, O., and Heineman, J., 1975, “von Karman Vortex Street in the Wake of Subsonic and Transonic Blades,” AGARD-CP-177, Unsteady Phenomena in Turbomachinery, Paper 28.
10.
Heinemann, J., and Bu¨tefisch, K. A., 1997, “Determination of the Vortex Shedding Frequency of Cascades with Different Trailing Edge Thicknesses,” AGARD-CP-227, Unsteady Aerodynamics, Paper 11.
11.
Carscallen, W. E., Feige, H. U., and Gostelow, J. P., 1996, “Transonic Turbine Vane Wake Flows,” ASME Paper No. 96-GT-419
12.
Cicatelli, G., and Sieverding, C. H., 1996, “A Review of the Research on Unsteady Turbine Blade Wake Characteristics,” AGARD-CP-571, Loss Mechanisms and Unsteady Flows in Turbomchines, Paper 6.
13.
Desse
,
J. M.
,
1998
, “
Effect of Time Varying Wake Characteristics Behind Flat Plates
,”
AIAA J.
,
36
(
11
), pp.
2036
–
2043
.
14.
Carscallen
,
W. E.
,
Currie
,
T. C.
,
Hogg
,
S. I.
, and
Gostelow
,
J. P.
,
1998
, “
Measurement and Computation of Energy Separation in Vortical Wake Flow of a Turbine Blade
,”
ASME J. Turbomach.
,
121
(
4
), pp.
703
–
708
.
15.
Arnone, A., and Pacciani, R., 1997, “Numerical Prediction of Trailing Edge Wake Shedding,” ASME Paper No. 97-GT-89.
16.
Manna
,
M.
,
Mulas
,
M.
, and
Cicatelli
,
G.
,
1997
, “
Vortex Shedding Behind a Blunt Trailing Edge Turbine Blade
,”
Int. J. Turbo Jet Engines
,
14
, pp.
145
–
157
.
17.
Sondak
,
D. L.
,
Dorney
,
D. J.
,
1998
, “
Simulation of Vortex Shedding in a Turbine Stage
,”
ASME J. Turbomach.
,
121
(
3
), pp.
428
–
435
.
18.
Sondak
,
L. D.
,
1999
, “
Vortex Shedding in a Turbine Cascade
,”
Int. J. Turbo Jet Engines
,
16
, pp.
107
–
126
.
19.
Currie
,
T. C.
, and
Carscallen
,
W. E.
,
1998
, “
Simulation of Trailing Edge Vortex Shedding in a Transonic Turbine Cascade
,”
ASME J. Turbomach.
,
120
(
1
), pp.
10
–
19
.
20.
Magagnato, F., 1999, “Unsteady Flow Past a Turbine Blade using Non-Linear Two-Equation Turbulence Models,” Proc., 3th European Turbomachinery Conference, London, United Kingdom.
21.
Sieverding, C. H., Cicatelli, G., Desse, J. M., Meinke, M., and Zunino, P., 1999, Experimental and Numerical Investigation of Time Varying Wakes behind Turbine Blades, Notes on Numerical Fluid Mechanics Volume 67, Vieweg.
22.
Sieverding
,
C. H.
, and
Heinemann
,
H.
,
1990
, “
The Influence of Boundary Layer State on Vortex Shedding from Flat Plates and Turbine Cascades
,”
ASME J. Turbomach.
,
112
(
2
), pp.
181
–
187
.
23.
Gerrard
,
J. H.
,
1966
, “
The Mechanism for the Formation Region of Vortices Behind Bluff Bodies
,”
J. Fluid Mech.
,
25
(
2
), pp.
401
–
413
.
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