This investigation is aimed at an experimental determination of the unsteady flowfield downstream of a transonic high pressure turbine stage. The single stage measurements, which were part of a joined European project, were conducted in the windtunnel for rotating cascades of the DLR Go¨ttingen. Laser-2-focus (L2F) measurements were carried out in order to determine the Mach number, flow angle, and turbulence distributions. Furthermore, a fast response pitot probe was utilized to determine the total pressure distribution. The measurement position for both systems was 0.5 axial rotor chord downstream of the rotor trailing edge at midspan. While the measurement position remained fixed, the nozzle guide vane (NGV) was “clocked” to 12 positions covering one NGV pitch. The periodic fluctuations of the total pressure downstream of the turbine stage indicate that the NGV wake damps the total pressure fluctuations caused by the rotor wakes. Furthermore, the random fluctuations are significantly lower in the NGV wake affected region. Similar conclusions were drawn from the L2F turbulence data. Since the location of the interaction between NGV wake and rotor wake is determined by the NGV position, the described effects are potential causes for the benefits of “stator clocking” which have been observed by many researchers.

Issue Section:
Technical Papers
Keywords:
gas turbines, stators, wakes, transonic flow, wind tunnels, rotational flow, Mach number, turbulence, fluctuations
Topics:
Flow (Dynamics), Mach number, Nozzle guide vanes, Pressure, Rotors, Stators, Turbines, Turbulence, Wakes, Fluctuations (Physics), Probes
1.
Arndt
,
N.
,
1993
, “
Blade Row Interaction in a Multistage Low-Pressure Turbine
,”
ASME J Turbomach.
,
115
, pp.
137
–
146
.
2.
Barankiewicz, W. S., and Hathaway, M. D., 1997, “Effects of Stator Indexing on Performance in a Low Speed Multistage Axial Compressor,” ASME Paper No. 97-GT-496.
3.
Saren, V. E., Savin, N. M., Dorney, D. J., and Sondak, D. L., 1998, “Experimental and Numerical Investigation of Airfoil Clocking and Inter-Blade-Row Gap Effects on Axial Compressor Performance,” AIAA Paper No. 98-3413.
4.
Dorney, D. J., Sondak, D. L., Cizmas P. G. A., Saren, V. E., and Savin, N. M., 1999, “Full-Annulus Simulations of Airfoil Clocking in a 1-1/2 Stage Axial Compressor,” ASME Paper No. 99-GT-23.
5.
Gundy-Burlet, Karen L., and Dorney, Daniel, J., 1997, “Physics of Airfoil Clocking in Axial Compressors,” ASME Paper No. 97-GT-444.
6.
Dorney, D. J., Sharma, O. P., and Gundy-Burlet, K. L., 1998, “Physics of Airfoil Clocking in a High Speed Axial Compressor,” ASME Paper No. 98-GT-82.
7.
Sharma, O. P., Ni, R. H., and Tanrikut, S., 1994, “Unsteady Flows in Turbines-Impact on Design Procedure,” AGARD-LS-195.
8.
Huber
,
F. W.
,
Johnson
,
P. D.
,
Sharma
,
O. P.
,
Staubach
,
J. B.
, and
Gaddis
,
S. W.
,
1996
, “
Performance Improvement Through Indexing of Turbine Airfoils: Part 1—Experimental Investigation
,”
ASME J. Turbomach.
,
118
, pp.
630
–
635
.
9.
Griffin
,
L. W.
,
Huber
,
F. W.
, and
Sharma
,
O. P.
,
1996
, “
Performance Improvement Through Indexing of Turbine Airfoils: Part 2—Numerical Simulation
,”
ASME J. Turbomach.
,
118
, pp.
636
–
642
.
1.
Halstead
,
D. E.
,
Wisler
,
D. C.
,
Okiishi
,
T. H.
,
Walker
,
G. J.
,
Hodson
,
H. P.
, and
Shin
,
H.-W.
,
1997
, “
Boundary Layer Development in Axial Compressors and Turbines,” Part 1 of 4—Composite Picture
,
ASME J. Turbomach.
,
119
, pp.
114
–
127
,
2.
Part 2 of 4—Compressors,
ASME J. Turbomach.
,
119
, pp.
426
–
444
,
1997
.
3.
Part 3 of 4—LP Turbines,
ASME J. Turbomach
,
119
, pp.
225
–
237
,
1997
.
4.
Part 4 of 4—Computations and Analyses,
ASME J. Turbomach.
,
119
, pp.
128
–
139
,
1997
.
1.
Eulitz, F., Engel, K., and Gebing, H., 1996, “Numerical Investigations of the Clocking Effects in a Multistage Turbine,” ASME Paper No. 96-GT-26.
2.
Dorney, D. J., and Sharma, O. P., 1996, “A Study of Turbine Performance Increases Through Airfoil Clocking,” AIAA Paper No. 96-2816.
3.
Blair
,
M. F.
,
Dring
,
R. P.
, and
Joslyn
,
H. D.
,
1988
, “
The Effects of Turbulence and Stator/Rotor Interactions on Turbine Heat Transfer, Part I—Design Operating Conditions
,”
ASME J. Turbomach.
,
111
, pp.
97
–
103
.
4.
Johnston, D. A., and Fleeter, S., 1999, “Turbine Blade Unsteady Heat Transfer Change Due to Stator Indexing,” ASME Paper No. 99-GT-376.
5.
Hsu
,
S. T.
, and
Wo
,
A. M.
,
1997
, “
Reduction of Unsteady Blade Loading by Beneficial Use of Vortical and Potential Disturbances in an Axial Compressor With Rotor Clocking
,”
ASME J. Turbomach.
,
120
, pp.
705
–
713
.
6.
Walker
,
G. J.
,
Hughes
,
J. D.
,
Ko¨hler
,
I.
, and
Solomon
,
W. J.
,
1998
, “
The Influence of Wake-Wake Interactions on Loss Fluctuations of a Downstream Axial Compressor Blade Row
,”
ASME J. Turbomach.
,
120
, pp.
695
–
704
.
7.
Kost, F., and Kapteijn, C., 1997, “Application of Laser-Two-Focus Velocimetry to Transonic Turbine Flows,” 7th Int. Conference on “Laser Anemometry—Advances and Applications,” Univ. of Karlsruhe, Germany, September 8–11.
8.
Tiedemann, M., 1998, “Stator Wake Effects on the Total Pressure Distribution Downstream of a Transonic Turbine Rotor,” Transactions of the Institute of Fluid-Flow Machinery of the Polish Academy of Science, No. 104, pp 3–18.
9.
Tiedemann, M., and Kost, F., 1999, “Unsteady Boundary Layer Transition on a High Pressure Turbine Rotor Blade,” ASME Paper No. 99-GT-194.
Copyright © 2001
 by ASME
You do not currently have access to this content.