The present work is part of the research project at the Institute of Jet Propulsion and Turbomachinery at the RWTH Aachen University in collaboration with GE Aviation. The subject is the numerical and experimental analysis of two blading strategies used in the diffusion system of an aero engine centrifugal compressor. The transonic centrifugal compressor investigated contains a close-coupled impeller and passage diffuser, followed by a deswirler system. The deswirler redirects the flow towards the combustion chamber, while decreasing swirl and recovering pressure. It is characterized by a high aerodynamic loading, due to a moderate inlet Mach number of 0.35, in combination with a required flow redirection of 70 deg in circumferential and 135 deg in meridional direction. For this purpose, two different blading strategies are investigated, both retaining the same meridional flow path and integral chord length. The first design is a tandem configuration with 30 vanes in the first row and 60 vanes in the second row. In principal, this approach benefits from the small wetted surface, the short and thereby stable boundary layers as well as the positive blade interaction due to the close alignment. The second design contains one row of 75 vanes. The higher solidity is needed to compensate for the longer boundary layers. The two deswirlers investigated are compared to a less compact baseline deswirler with simple prismatic vanes. Experimental and numerical data shows that both new configurations have very similar stage efficiency. The single row design shows a higher static pressure recovery, resulting in a +0.2%-points total-to-static isentropic efficiency increase compared to the tandem design. Detailed flow analysis in the deswirler system shows different characteristics in terms of losses, loss mechanisms and pressure build-up. Due to the required high turning, both designs suffer from flow separation. Nevertheless, the single row design shows its robustness under the impact of 3D flow, whereas the tandem suffers from end wall induced losses. The results show that the classical mechanisms making a tandem favorable for high flow turning in 2D flow are counteracted by 3D flow mechanisms caused by the spanwise pressure gradient. The low aspect ratio even increases the effect of 3D end wall mechanisms. These results, combined with a higher manufacturing effort, show that a tandem configuration is not necessarily the superior design for highly 3D flow conditions.

References

References
1.
Hill
,
P.
, and
Peterson
,
C.
,
1992
,
Mechanics and Thermodynamics of Propulsion
,
2nd ed.
Addison-Wesley
,
New York
.
2.
Wilfert
,
G.
,
Sieber
,
J.
,
Rolt
,
A.
,
Baker
,
N.
,
Touyeras
,
A.
, and
Colantuoni
,
S.
,
2007
, “
New Environmental Friendly Aero Engine Core Concepts
,” 18th
ISABE
Conference, Beijing, September 2–7, Paper No. ISABE-2007-1120.
3.
Bryans
,
A.
,
1986
, “
Diffuser for a Centrifugal Compressor
,” U.S. Patent No, 4,576,550, pp. 8.
4.
Zachau
,
U.
,
2007
, “
Experimental Investigation on the Diffuser Flow of a Centrifugal Compressor Stage With Pipe Diffuser
,” Ph.D. thesis, RWTH Aachen, Aachen, Germany.
5.
Kunte
,
R.
,
Jeschke
,
P.
, and
Smytheza
,
C.
,
2012
, “
Experimental Investigation of a Trauncated Pipe Diffuser With a Tandem Deswirler in a Centrifugal Compressor Stage
,”
ASME Turbo Expo 2012: Turbine Technical Conference and Exposition, Copenhagen, Denmark, June 11–15
,
ASME
Paper No. GT2012-68449. 10.1115/GT2012-68449
6.
Schwarz
,
P.
,
Wilkosz
,
B.
,
Kunte
,
R.
,
Schmidt
,
J.
,
Jeschke
,
P.
, and
Smythe
,
C.
,
2012
, “
Numerical Investigation Into the Ratio Between Passage Diffuser and Vaneless Diffuser in a Centrifugal Compressor Stage
,”
61. Deutscher Luft- und Raumfahrtkongress
.
7.
McGlumphy
,
J.
,
2008
. “
Numerical Investigation of Subsonic Axial-Flow Tandem Airfoils for a Core Compressor Rotor
,” Ph.D. thesis, Virginia Polytechnic Institute and State University, Blacksburg, VA.
8.
Orth
,
U.
,
Ebbing
,
H.
,
Krain
,
H.
, and
Hoffmann
,
A. W. B.
,
2002
, “
Improved Compressor Exit Diffuser for an Industrial Gas Turbine
,”
ASME J. Turbomach.
,
124
, pp.
19
26
.10.1115/1.1413476
9.
Smith
,
A.
,
1975
, “
High-Lift Aerodynamics
,”
J. Aircraft
,
12
(6), pp.
501
530
.
10.
Japikse
,
D.
,
1988
,
Centrifugal Compressor Design and Performance
,
9th ed.
,
Concepts ETI
,
Norwich, VT
.
11.
Braeunling
,
W. J. G.
,
2009
,
Flugzeugtriebwerke: Grundlagen, Aero-Thermodynamik, ideale und reale Kreisprozesse, Thermische Turbomaschinen, Komponenten, Emissionen und Systeme
,
Springer
,
Berlin
, Chap. 10.
12.
Sakaguchi
,
D.
,
Ueki
,
H.
,
Ishida
,
M.
, and
Hayami
,
H.
,
2012
, “
Behavior of Secondary Flow in a Low Solidity Tandem Cascade Diffuser
,”
ASME
Paper No. GT2012-69369. 10.1115/GT2012-69369
13.
Senoo
,
Y.
,
Hayami
,
H.
, and
Ueki
,
H.
,
1983
, “
Low-Solidity Tandem-Cascade Diffusers for Wide-Flow-Range Centrifugal Blowers
,”
ASME
Paper No. 83-GT-3.
14.
Railly
,
J.
, and
El-Sarha
,
M.
,
1965
, “
An Investigation of the Flow Through Tandem Cascades
,”
Proceed. Instit. Mech. Eng., Conf. Proceed. June 1965
,
180
(10), pp.
66
73
.10.1243/PIME_CONF_1965_180_282_02
15.
Guochuan
,
W.
,
Biaonan
,
Z.
, and
Bingheng
,
G.
,
1988
, “
Experimental Investigation of Tandem Blade Cascades With Double-Circular Arc Profiles
,”
Int. J. Turbo Jet Eng.
,
5
, pp.
163
169
.
16.
McGlumphy
,
J.
,
Wing-Fai
,
N.
,
Wellborn
,
S. R.
, and
Kempf
,
S.
,
2009
, “
Numerical Investigation of Tandem Airfoils for Subsonic Axial-Flow Compressor Blades
,”
ASME J. Turbomach.
,
131
, p.
021018
.10.1115/1.2952366
17.
Baumert
,
A.
,
2012
, “
Abschaetzung der Stroemungsverluste in Verdichter-Tandemgittern
,”
DLRK Proceedings
.
18.
Yuping
,
Q.
,
Zhiping
,
L.
,
Yajun
,
L.
, and
Qiushi
,
L.
,
2012
, “
Flow Mechanics in Tandem Rotors
,”
ASME
Paper No. GT2012-69665. 10.1115/GT2012-69665
19.
Roberts
,
D.
, and
Kacker
,
S.
,
2002
, “
Numerical Investigation of Tandem-Impeller Designs for a Gas Turbine Compressor
,”
ASME J. Turbomach.
,
124
, pp.
36
44
.10.1115/1.1413472
20.
Josuhn-Kadner
,
B.
,
1994
, “
Flow Field and Performance of a Centrifugal Compressor Rotor With Tandem Blades of Adjustable Geometry
,” ASME Paper No. 94-GT-041.
21.
Sakai
,
Y.
,
Matsuoka
,
A.
,
Suga
,
S.
, and
Hashimoto
,
K.
,
2003
, “
Design and Test of Transonic Compressor Rotor With Tandem Cascade
,”
Proceedings of the International Gas Turbine Congress 2003
,
Tokyo
, November 2–7, Paper No. IGTC2003Tokyo TS-108.
22.
Denton
,
J.
, and
Cumpsty
,
N.
,
1987
, “
Loss Mechanisms in Turbomachines
,”
Turbomachinery/Efficiency Prediction and Improvement, International Conference, Proceedings of the Institution of Mechanical Engineers
, Cambridge, UK, September 1–3, Paper No. C260/87.
23.
Denton
,
J.
, and
Xu
,
L.
,
1999
, “
Turbomachinery Blade Design Systems
,” von Karman Institute for Fluid Dynamics Lecture Series 1999–2012.
24.
Kunte
,
R.
,
Schwarz
,
P.
,
Wilkosz
,
B.
,
Jeschke
,
P.
, and
Smythe
,
C.
,
2013
, “
Experimental and Numerical Investigation of Tip Clearance and Bleed Effects in a Centrifugal Compressor Stage With Pipe Diffuser
,”
ASME J. Turbomach.
,
135
(
1
), p.
011005
.10.1115/1.400631810.1115/1.4007526
25.
Roe
,
P.L.
,
1981
, “
Approximate Riemann Solvers, Parameter Vectors, and Difference Schemes
,”
J. Comput. Phys.
,
43
, pp.
357
372
.10.1016/0021-9991(81)90128-5
26.
Kuegeler
,
E.
,
2004
, “
Numerisches Verfahren Zur Genauen Analyse der Kuehleffektivitaet Filmgekuehlter Turbinenschaufeln
,” Ph.D. thesis, DLR, Ruhr Universitaet Bochum, Cologne, Germany.
27.
Giles
,
M.
,
1988
, “
Non-Reflecting Boundary Conditions for the Euler Equations
,” MIT Dept. Aernaut. Astronaut., Paper No. CFDL-TR-88-1.
28.
Wilcox
,
D.C.
,
1994
, “
Turbulence Modeling for CFD
,” DCW Industries Inc., La Canada, CA.
29.
Kozulovic
,
D.
, and
Roeber
,
T.
,
2006
, “
Modelling the Streamline Curvature Effects in Turbomachinery Flows
,”
ASME Turbo Expo 2006: Power for Land, Sea, and Air, Barcelona, Spain, May 8–11
,
ASME
Paper No. GT2006-90265 10.1115/GT2006-90265.
30.
Kozulovic
,
D.
,
Roeber
,
T.
,
Kuegeler
,
E.
, and
Nuernberger
,
D.
,
2004
, “
Modifications of a Two-Equation Turbulence Model for Turbomachinery Fluid Flows
,” DLR Institute of Propulsion Technology, Cologne, Germany.
31.
Wilkosz
,
B.
,
Zimmermann
,
M.
,
Schwarz
,
P.
,
Jeschke
,
P.
, and
Smythe
,
C.
,
2013
, “
Numercial Investigation of the Unsteady Interaction Within a Close-Coupled Centrifugal Compressor Used in an Aero Engine
,”
Proceedings of ASME Turbo Expo
, San Antonio, TX, June 3–7, ASME Paper No. GT2013-95644.
32.
Guenther
,
C.
,
2012
, “
Numerische und Experimentelle Analyse Von Zwei Neuartigen Strategien Zur Diffusorbeschaufelung Eines Radialen Triebwerkverdichters
,” M.S. thesis, RWTH Aachen University Institut fuer Strahlantriebe und Turboarbeitsmaschinen, Aachen, Germany.
33.
Wilkosz
,
B.
,
Schwarz
,
P.
,
Kunte
,
R.
,
Jeschke
,
P.
, and
Smythe
,
C.
,
2012
, “
Numerical and Experimental Investigation of an Impeller Tip Clearance Variation in a Centrifugal Compressor Stage With Pipe-Diffuser
,”
Proceedings DLRK 2012 Conference
, Paper No. DLRk-2012-281271.
34.
Denton
,
J.
,
1993
, “
Loss Mechanisms in Turbomachines
,”
ASME J. Turbomach.
,
115
(
1993
), pp.
621
656
.10.1115/1.2929299
35.
Dawes
,
W.
,
1994
, “
A Numerical Study of the Interaction of a Transonic Compressor Rotor Overtip Leakage Vortex With the Following Stator Blade Row
,”
ASME
Paper No. 94-GT-156.
36.
Drela
,
M.
, and
Youngren
,
H.
,
2008
, “
A User's Guide to Mises 2.63
,” MIT Aerospace Computational Design Laboratory, Tech. Rep. February.
This content is only available via PDF.

Article PDF first page preview

Article PDF first page preview
You do not currently have access to this content.