This paper investigates the flow near the stall boundary for a low-speed/low-pressure ratio fan. Three-dimensional, Reynolds-averaged Navier–Stokes computations are performed for a modern low speed fan rig for which extensive measured data are available. Simulations are conducted at 80% corrected speed, for which the measured constant speed characteristic contains a part with positive slope. It is shown in this paper that by using an unsteady whole assembly approach, it is possible to predict the flow for all the points on the measured constant speed characteristic (including those on the positive slope part), which is not achievable by using a single passage strategy as it would result in premature “numerical stall.” The results of the computations reveal that for the operating points on the positive slope part of the characteristic, the flow structure becomes asymmetric and hence requires a whole assembly numerical model. The type of asymmetry which appears at lower flow coefficients is similar to the multicell, part span rotating stall, which can occur on the front stages of core compressors at stable operating conditions. The numerical results showed a good correlation with the measured data in terms of stall characteristics.

References

References
1.
Liu
,
Y.
,
Lu
,
L.
,
Fang
,
L.
, and
Gao
,
F.
,
2011
, “
Modification of Spalart–Allmaras Model With Consideration of Turbulence Energy Backscatter Using Velocity Helicity
,”
Phys. Lett.
,
375
(
24
), pp.
2377
2381
.
2.
Li
,
M.
,
Lipeng
,
L.
,
Jian
,
F.
, and
Qiuhui
,
W.
,
2014
, “
A Study on Turbulence Transportation and Modification of Spalart–Allmaras Model for Shock-Wave/Turbulent Boundary Layer Interaction Flow
,”
Chin. J. Aeronaut.
,
27
(
2
), pp.
200
209
.
3.
Young
,
A.
,
Day
,
I.
, and
Pullan
,
G.
,
2013
, “
Stall Warning by Blade Pressure Signature Analysis
,”
ASME J. Turbomach.
,
135
(
1
), p.
011033
.
4.
Day
,
I.
,
1993
, “
Stall Inception in Axial Flow Compressors
,”
ASME J. Turbomach.
,
115
(
1
), pp.
1
9
.
5.
Camp
,
T.
, and
Day
,
I.
,
1998
, “
A Study of Spike and Modal Stall Phenomena in a Low-Speed Axial Compressor
,”
ASME J. Turbomach.
,
120
(
3
), pp.
393
401
.
6.
Vo
,
H. D.
,
Tan
,
C. S.
, and
Greitzer
,
E. M.
,
2008
, “
Criteria for Spike Initiated Rotating Stall
,”
ASME J. Turbomach.
,
130
(
1
), p.
011023
.
7.
Pullan
,
G.
,
Young
,
A.
,
Day
,
I.
,
Greitzer
,
E.
, and
Spakovszky
,
Z.
,
2015
, “
Origins and Structure of Spike-Type Rotating Stall
,”
ASME J. Turbomach.
,
137
(
5
), p.
051007
.
8.
Choi
,
M.
,
Vahdati
,
M.
, and
Imregun
,
M.
,
2011
, “
Effects of Fan Speed on Rotating Stall Inception and Recovery
,”
ASME J. Turbomach.
,
133
(
4
), p.
041013
.
9.
Choi
,
M.
,
Smith
,
N. H.
, and
Vahdati
,
M.
,
2013
, “
Validation of Numerical Simulation for Rotating Stall in a Transonic Fan
,”
ASME J. Turbomach.
,
135
(
2
), p.
021004
.
10.
Dodds
,
J.
, and
Vahdati
,
M.
,
2015
, “
Rotating Stall Observations in a High Speed Compressor—Part I: Experimental Study
,”
ASME J. Turbomach.
,
137
(
5
), p.
051002
.
11.
Dodds
,
J.
, and
Vahdati
,
M.
,
2015
, “
Rotating Stall Observations in a High Speed Compressor—Part II: Numerical Study
,”
ASME J. Turbomach.
,
137
(
5
), p.
051003
.
12.
Sayma
,
A. I.
,
Vahdati
,
M.
,
Sbardella
,
L.
, and
Imregun
,
M.
,
2000
, “
Modeling of Three-Dimensional Viscous Compressible Turbomachinery Flows Using Unstructured Hybrid Grids
,”
AIAA J.
,
38
(
6
), pp.
945
954
.
13.
Vahdati
,
M.
,
Sayma
,
A.
,
Freeman
,
C.
, and
Imregun
,
M.
,
2005
, “
On the Use of Atmospheric Boundary Conditions for Axial-Flow Compressor Stall Simulations
,”
ASME J. Turbomach.
,
127
(
2
), pp.
349
351
.
14.
Lee
,
K.-B.
,
Wilson
,
M.
, and
Vahdati
,
M.
,
2016
, “
Numerical Study on Aeroelastic Instability for a Low Speed Fan
,”
ASME J. Turbomach.
,
139
(
7
), p.
071004
.
15.
Vahdati
,
M.
, and
Cumpsty
,
N.
,
2015
, “
Aeroelastic Instability in Transonic Fans
,”
ASME J. Eng. Gas Turbines Power
,
138
(
2
), p.
022604
.
16.
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
.
17.
Pardowitz
,
B.
,
Tapken
,
U.
,
Sorge
,
R.
,
Thamsen
,
P. U.
, and
Enghardt
,
L.
,
2014
, “
Rotating Instability in an Annular Cascade: Detailed Analysis of the Instationary Flow Phenomena
,”
ASME J. Turbomach.
,
136
(
6
), p.
061017
.
18.
Mailach
,
R.
,
Lehmann
,
I.
, and
Vogeler
,
K.
,
2001
, “
Rotating Instabilities in an Axial Compressor Originating From the Fluctuating Blade Tip Vortex
,”
ASME J. Turbomach.
,
123
(
3
), pp.
453
460
.
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