Unshrouded industrial centrifugal compressor impellers operate at high rotational speeds and volume flow rates. Under such conditions, the main impeller blade excitation is dominated by high frequency interaction with stationary parts, i.e., vaned diffusers or inlet guide vanes (IGVs). However, at severe part load operating conditions, sub-synchronous rotating flow phenomena (rotating stall) can occur and cause resonant blade vibration with significant dynamic (von-Mises) stress in the impeller blades. To ensure high aerodynamic performance and mechanical integrity, part load conditions must be taken into account in the aeromechanical design process via computational fluid dynamics (CFD) and finite element method (FEM) analyzes anchored by experimental verification. The experimental description and quantification of unsteady interaction between rotating stall cells and an unshrouded centrifugal compression stage in two different full scale compression units by Jenny and Bidaut (“Experimental Determination of Mechanical Stress Induced by Rotating Stall in Unshrouded Impellers of Centrifugal Compressors”, ASME J. Turbomach. 2016; 139(3):031011-031011-10) were reproduced in a scaled model test facility to enhance the understanding of the fluid–structure interaction (FSI) mechanisms and to improve design guide lines. Measurements with strain gauges and time-resolved pressure transducers on the stationary and rotating parts at different positions identified similar rotating stall patterns and induced stress levels. Rotating stall cell induced resonant blade vibration was discovered for severe off-design operating conditions and the measured induced dynamic von-Mises stress peaked at 15% of the mechanical endurance limit of the impeller material. Unsteady full annulus CFD simulations predicted the same rotating stall pressure fluctuations as the measurements. The unsteady Reynold's Averaged Navier-Stokes simulations were then used in FEM FSI analyses to predict the stress induced by rotating stall and assess the aerodynamic damping of the corresponding impeller vibration mode shape. Excellent agreement with the measurements was obtained for the stall cell pressure amplitudes at various locations. The relative difference between measured and mean predicted stress from fluid–structure interaction was 17% when resonant blade vibration occurred. The computed aerodynamic damping was 27% higher compared to the measurement.

References

References
1.
Jenny
,
P.
, and
Bidaut
,
Y.
,
2016
, “
Experimental Determination of Mechanical Stress Induced by Rotating Stall in Unshrouded Impellers of Centrifugal Compressors
,”
ASME J. Turbomach.
,
139
(
3
), p.
031011
.
2.
Hunziker
,
R.
, and
Gyarmathy
,
G.
,
1994
, “
The Operational Stability of a Centrifugal Compressor and Its Dependence on the Characteristics of the Subcomponents
,”
ASME J. Turbomach.
,
116
(
2
), pp.
250
259
.
3.
Ribi
,
B.
, and
Gyarmathy
,
G.
,
1993
, “
Impeller Rotating Stall as T Rigger for the Transition From Mild to Deep Surge in a Subsonic Centrifugal Compressor
,”
ASME
Paper No. 93-GT-234.
4.
Ribi
,
B.
,
1996
, “
Centrifugal Compressors in the Unstable Flow Regime
,” Doctoral thesis, Swiss Federal Institute of Technology, Zurich, Switzerland.
5.
Gyarmathy
,
G.
, and
Staubli
,
T.
,
1997
, “
Water Model of a Single-Stage Centrifugal Compressor for Studying Rotating Stall
,”
Second European Conference on Turbomachinery—Fluid Dynamics and Thermodynamics
, Antwerp, Belgium, Mar. 5–7, pp.
317
327
.
6.
Gyarmathy
,
G.
,
1996
, “
Impeller-Diffuser Momentum Exchange During Rotating Stall
,”
ASME
Paper No. 96-WA/PID-6.
7.
Haupt
,
U.
,
Seide
,
U.
,
Abdel-Hamid
,
A. N.
, and
Rautenberg
,
M.
,
1988
, “
Unsteady Flow in a Centrifugal Compressor With Different Types of Vaned Diffusers
,”
ASME J. Turbomach.
,
110
(
3
), pp.
293
302
.
8.
Van Den Braembussche
,
R.
,
1982
,
“Rotating Stall in Vaneless Diffusers of Centrifugal Compressors,”
Van Karman Institute for Fluid Dynamics
, Sint-Genesius-Rode, Belgium.
9.
Everitt
,
J. N.
, and
Spakovszky
,
Z. S.
,
2013
, “
An Investigation of Stall Inception in Centrifugal Compressor Vaned Diffuser
,”
ASME J. Turbomach.
,
135
(
1
), p.
011025
.
10.
Spakovszky
,
Z. S.
,
2004
, “
Backward Traveling Rotating Stall Waves in Centrifugal Compressors
,”
ASME J. Turbomach.
,
126
(
1
), pp.
1
12
.
11.
Spakovszky
,
Z. S.
, and
Roduner
,
C. H.
,
2009
, “
Spike and Modal Stall Inception in an Advanced Turbocharger Centrifugal Compressor
,”
ASME J. Turbomach.
,
131
(
3
), p.
031012
.
12.
Longley
,
J.
,
1994
, “
A Review of Nonsteady Flow Models for Compressor Stability
,”
ASME J. Turbomach.
,
117
(
2
), pp.
202
215
.
13.
He
,
L.
, and
Ning
,
W.
,
1998
, “
An Efficient Approach for Analysis of Unsteady Viscous Flows in Turbomachinery
,”
AIAA J.
,
36
(
11
), pp.
2005
2012
.
14.
Ning
,
W.
, and
He
,
L.
,
1998
, “
Computation of Unsteady Flows Around Oscillating Blades Using Linear and Nonlinear Harmonic Euler Methods
,”
ASME J. Turbomach.
,
120
(
3
), pp.
508
514
.
15.
Biesinger
,
T.
,
Cornelius
,
C.
,
Rube
,
C.
,
Braune
,
A.
,
Schmid
,
G.
,
Campregher
,
R.
, and
Godin
,
P. G.
,
2010
, “
Unsteady CFD Methods in a Commercial Solver for Turbomachinery Applications
,”
ASME
Paper No. GT2010-22762.
16.
Blumenthal
,
R.
,
Hutchinson
,
B.
, and
Zori
,
L.
,
2011
, “
Investigation of Transient CFD Methods Applied to a Transonic Compressor Stage
,”
ASME
Paper No. GT2011-46635.
17.
Dickmann
,
H.-P.
,
Secall Wimmel
,
T.
,
Szwedowicz
,
J.
,
Kühnel
,
J.
, and
Essig
,
U.
,
2009
, “
Unsteady Flow in a Turbocharger Centrifugal Compressor: 3D-CFD Simulation, Impeller Blade Vibration and Vaned Diffuser-Volute Interaction
,”
ASME
Paper No. GT2009-59046.
18.
Marconcini
,
M.
,
Bianchini
,
A.
,
Checcucci
,
M.
,
Ferrara
,
G.
,
Arnone
,
A.
,
Ferrari
,
L.
,
Biliotti
,
D.
, and
Tommaso Rubino
,
D.
,
2016
, “
A 3D Time-Accurate CFD Simulation of the Flow Field in a Vaneless Diffuser Under Rotating Stall Conditions
,”
ASME
Paper No. GT2016-57604.
19.
Ewins
,
D. J.
,
2000
, “
Modal Testing Theory, Practice and Applications
,”
2nd ed.
,
Research Studies Press
,
Baldock, Hertfordshire, UK
.
20.
Bidaut
,
Y.
, and
Baumann
,
U.
,
2012
, “
Identification of Eigenmodes and Determination of the Dynamical Behaviour of Open Impellers
,”
ASME
Paper No. GT2012-68182.
21.
Kielb
,
R.
,
Barter
,
J.
,
Chernycheva
,
O.
, and
Fransson
,
T.
,
2004
, “
Flutter of Low Pressure Turbine Blades With Cyclic Symmetric Modes: A Preliminary Design Method
,”
ASME J. Turbomach.
,
126
(
2
), pp.
306
309
.
22.
Carta
,
F. O.
,
1967
, “
Coupled Blade-Disk-Shroud Flutter Instabilities in Turbojet Engine Rotors
,”
ASME J. Eng. Power
,
89
(
3
), pp.
419
426
.
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