This paper describes observed modal oscillations arising from a feedback mechanism between an acoustic resonance in the exit flow channel and aerodynamic and aeroelastic disturbances in a transonic fan stage. During tests, the fan suffered from rotating stall and surge which were preceded by low frequency pressure fluctuations. Through a range of aerodynamic and aeromechanical instrumentations, it was possible to determine a clear chain of cause and effect, whereby geometrical asymmetries trigger local instabilities and modal oscillations through an interaction with the system acoustics. To the authors knowledge, this is the first time that modal oscillations occurring before stall are attributed to multiphysical interactions, showing that acoustic characteristics of the system can influence the aerodynamic as well as the aeromechanical stability of fans. This bears implications for the stability assessment of fans and compressors because first, the stability margin may be affected by standing waves generated in bypass ducts or combustion chambers, and second, geometrical variations of the rotor blades which are believed to be beneficial for aeromechanical stability may lead to complex coupling phenomena.

References

References
1.
Camp
,
T. R.
, and
Day
,
I. J.
,
1998
, “
A Study of Spike and Modal Stall Phenomena in a Low-Speed Axial Compressor
,”
ASME J. Turbomach.
,
120
(
3
), pp.
393
401
.
2.
Moore
,
F.
,
1984
, “
A Theory of Rotating Stall of Multistage Axial Compressors—Part I: Small Disturbances
,”
ASME J. Eng. Gas Turbines Power
,
106
(
2
), pp.
313
320
.
3.
Moore
,
F.
,
1984
, “
A Theory of Rotating Stall of Multistage Axial Compressors—Part II: Finite Disturbances
,”
ASME J. Eng. Gas Turbines Power
,
106
(
2
), pp.
321
326
.
4.
Moore
,
F.
,
1984
, “
A Theory of Rotating Stall of Multistage Axial Compressors—Part III: Limit Cycles
,”
ASME J. Eng. Gas Turbines Power
,
106
(
2
), pp.
327
334
.
5.
McDougall
,
N.
,
Cumpsty
,
N.
, and
Hynes
,
T.
,
1990
, “
Stall Inception in Axial Compressors
,”
ASME J. Turbomach.
,
112
(
1
), pp.
116
123
.
6.
Garnier
,
V.
,
Epstein
,
A.
, and
Greitzer
,
E.
,
1991
, “
Rotating Waves as a Stall Inception Indicator in Axial Compressors
,”
ASME J. Turbomach.
,
113
(
2
), pp.
290
301
.
7.
Tryfonidis
,
M.
,
Etchevers
,
O.
,
Paduano
,
J.
,
Epstein
,
A.
, and
Hendricks
,
G.
,
1995
, “
Pre-Stall Behaviour of Several High-Speed Compressors
,”
ASME J. Turbomach.
,
117
(
1
), pp.
62
80
.
8.
Bright
,
M. M.
,
Qammar
,
H. K.
, and
Leizhen
,
W.
,
1999
, “
Investigation of Pre-stall Mode and Pip Inception in High-Speed Compressors Through the Use of Correlation Integral
,”
ASME J. Turbomach.
,
121
(
4
), pp.
743
750
.
9.
Jackson
,
A.
,
1986
, “
Stall Cell Development in an Axial Compressor
,”
ASME J. Turbomach.
,
109
(
4
), pp.
492
498
.
10.
Day
,
I.
,
1993
, “
Stall Inception in Axial Flow Compressors
,”
ASME J. Turbomach.
,
115
(
1
), pp.
1
9
.
11.
Young
,
A.
,
Day
,
I.
, and
Pullan
,
G.
,
2013
, “
Stall Warning by Blade Pressure Signature Analysis
,”
ASME J. Turbomach.
,
135
(
1
), p.
011033
.
12.
Inoue
,
M.
,
Kuroumaru
,
M.
,
Tanino
,
T.
, and
Furukawa
,
M.
,
2000
, “
Propagation of Multiple Short-Length-Scale Stall Cells in an Axial Compressor Rotor
,”
ASME J. Turbomach.
,
122
(
1
), pp.
45
54
.
13.
März
,
J.
,
Hah
,
C.
, and
Neise
,
W.
,
2002
, “
An Experimental and Numerical Investigation Into the Mechanisms of Rotating Instability
,”
ASME J. Turbomach.
,
124
(
3
), pp.
367
374
.
14.
Hah
,
C.
,
2016
, “
Effects of Double-Leakage Tip Clearance Flow on the Performance of a Compressor Stage With a Large Rotor Tip Gap
,”
ASME
Paper No. GT2016-56050.
15.
Mailach
,
R.
,
Lehman
,
I.
, and
Vogeler
,
K.
,
2018
, “
Rotating Instabilities in an Axial Compressor Originating From the Fluctuating Blade Tip Vortex
,”
ASME J. Turbomach.
,
123
(
3
), pp.
453
460
.
16.
Kielb
,
R. E.
,
Barter
,
J. W.
,
Thomas
,
J. P.
, and
Hall
,
K. C.
,
2003
, “
Blade Excitation by Aerodynamic Instabilities: A Compressor Blade Study
,”
ASME
Paper No. GT2003-38634.
17.
Brandstetter
,
C.
,
Juengst
,
M.
, and
Schiffer
,
H.-P.
,
2018
, “
Measurements of Radial Vortices, Spill Forward, and Vortex Breakdown in a Transonic Compressor
,”
ASME J. Turbomach.
,
140
(
6
), p.
061004
.
18.
Pullan
,
G.
,
Young
,
A. M.
,
Day
,
I. J.
,
Greitzer
,
E. M.
, and
Spakovszky
,
Z. S.
,
2015
, “
Origins and Structure of Spike-Type Rotating Stall
,”
ASME J. Turbomach.
,
137
(
5
), p.
51007
.
19.
Yamada
,
K.
,
Kikuta
,
H.
,
Iwakiri
,
K.-I.
,
Furukawa
,
M.
, and
Gunjishima
,
S.
,
2013
, “
An Explanation for Flow Features of Spike-Type Stall Inception in an Axial Compressor Rotor
,”
ASME J. Turbomach.
,
135
(
2
), p.
021023
.
20.
Hendricks
,
G.
,
Bonnaure
,
L.
,
Longley
,
J.
,
Greitzer
,
E.
, and
Epstein
,
A.
,
1993
, “
Analysis of Rotating Stall Onset in High Speed Axial Flow Compressors
,”
AIAA
Paper No. 93-2233.
21.
Wilson
,
M. J.
,
Imregun
,
M.
, and
Sayma
,
A. I.
,
2006
, “
The Effect of Stagger Variability in Gas Turbine Fan Assemblies
,”
ASME J. Turbomach.
,
129
(
2
), pp.
404
411
.
22.
Schreiber
,
J.
,
Paoletti
,
B.
, and
Ottavy
,
X.
,
2016
, “
Observations on Rotating Instabilities and Spike Type Stall Inception in a High-Speed Multistage Compressor
,”
Int. J. Rotating Mach.
,
2017
, p.
7035870
.
23.
Greitzer
,
E.
,
1976
, “
Surge and Rotating Stall in Axial Flow Compressors-Part I
,”
ASME J. Eng. Gas Turbines Power
,
98
(
2
), pp.
190
211
.
24.
Greitzer
,
E.
,
1976
, “
Surge and Rotating Stall in Axial Flow Compressors-Part II
,”
ASME J. Eng. Gas Turbines Power
,
98
(
2
), pp.
190
211
.
25.
Day
,
I.
,
1994
, “
Axial Compressor Performance During Surge
,”
J. Propul. Power
,
10
(
3
), pp.
329
336
.
26.
Courtiade
,
N.
, and
Ottavy
,
X.
,
2013
, “
Study of the Acoustic Resonance Occurring in a Multistage High-Speed Axial Compressor
,”
Proc. Inst. Mech. Eng., Part A
,
227
(
6
), pp.
654
664
.
27.
Lu
,
Y.
,
Green
,
J.
, and
Vahdati
,
M.
,
2018
, “
Effect of Geometry Variability on Fan Performance and Aeromechanical Characteristics
,” 15th International Symposium on Unsteady Aerodynamics, Aeroacoustics and Aeroelasticity of Turbomachines, Oxford, UK, Sept. 24–27, Paper No. ISUAAAT15-095.
28.
Srinivasan
,
A. V.
,
1980
, “
Influence of Mistuning on Blade Torsional Flutter
,” National Aeronautics and Space Administration, Washington, DC, Report No.
NASA CR-165137
.https://ntrs.nasa.gov/search.jsp?R=19800022846
29.
Castanier
,
M.
, and
Pierre
,
C.
,
2002
, “
Using Intentional Mistuning in the Design of Turbomachinery Rotors
,”
AIAA J.
,
40
(
10
), pp.
2077
2086
.
30.
Kielb
,
R. E.
,
Feiner
,
D.
,
Griffin
,
J. H.
, and
Mizakozawa
,
T.
,
2007
, “
The Effect of Unsteady Aerodynamic Asymmetric Perturbations on Flutter
,”
ASME
Paper No. GT2007-27503.
31.
Corral
,
R.
, and
Martel
,
C.
,
2012
, “
Mistuning Effects on Flutter Margin
,” NATO, Brussels, Belgium, Report No. NATO RTO-EN-AVT-207.
You do not currently have access to this content.