The performance of a transonic fan operating within nonuniform inlet flow remains a key concern for the design and operability of a turbofan engine. This paper applies computational methods to improve the understanding of the interaction between a transonic fan and an inlet total pressure distortion. The test case studied is the NASA rotor 67 stage operating with a total pressure distortion covering a 120-deg sector of the inlet flow field. Full-annulus, unsteady, three-dimensional CFD has been used to simulate the test rig installation and the full fan assembly operating with inlet distortion. Novel post-processing methods have been applied to extract the fan performance and features of the interaction between the fan and the nonuniform inflow. The results of the unsteady computations agree well with the measurement data. The local operating condition of the fan at different positions around the annulus has been tracked and analyzed, and this is shown to be highly dependent on the swirl and mass flow redistribution that the rotor induces ahead of it due to the incoming distortion. The upstream flow effects lead to a variation in work input that determines the distortion pattern seen downstream of the fan stage. In addition, the unsteady computations also reveal more complex flow features downstream of the fan stage, which arise due to the three dimensionality of the flow and unsteadiness.

References

1.
Ehrich
,
F.
, 1957, “
Circumferential Inlet Distortions in Axial Flow Turbomachinery
,”
J. Aero. Sci.
,
1
, pp.
413
417
.
2.
Seidel
,
B. S.
, 1964, “
Asymmetric Inlet Flow in Axial Turbomachines
,”
ASME J. Eng. Power
,
1
, pp.
18
28
.
3.
Doyle
,
M. D. C.
, and
Horlock
,
J. H.
, 1966, “
Circumferential Asymmetry in Axial Flow Compressors
,”
J. R. Aero. Soc.
,
70
, pp.
956
957
.
4.
Plourde
,
G. A.
, and
Stenning
,
A. H.
, 1968, “
Attenuation of Circumferential Inlet Distortion in Multistage Axial Compressors
,”
J. Aircraft
,
5-3
, pp.
238
242
.
5.
Callahan
,
G. M.
, and
Stenning
,
A. H.
, 1971, “
Attenuation of Inlet Flow Distortion Upstream of Axial Flow Compressors
,”
J. Aircraft
,
8-4
, pp.
227
233
.
6.
Henderson
,
R. E.
, and
Horlock
,
J. H.
, 1972, “
An Approximate Analysis of the Unsteady Lift on Airfoils in Cascade
,”
ASME J. Eng. Power
,
1
, pp.
233
240
.
7.
Greitzer
,
E. M.
, 1973, “
Upstream Attenuation and Quasi-Steady Rotor Lift Fluctuations in Asymmetric Flows in Axial Flow Compressors
,” ASME Paper 73-GT-30.
8.
Horlock
,
J. H.
,
Greitzer
,
E. M.
, and
Henderson
,
R. E.
, 1977, “
The Response of Turbomachinery Blades to Low Frequency Inlet Distortions
,”
ASME J. Eng. Power
,
1
, pp.
195
203
.
9.
Greitzer
,
E. M.
, and
Strand
,
T.
, 1978, “
Asymmetric Swirling Flows in Turbomachinery Annuli
,”
ASME J. Eng. Power
,
100
, pp.
618
629
.
10.
Stenning
,
A. H.
, 1980, “
Inlet Distortion Effects in Axial Compressors
,”
ASME J. Fluids Eng.
,
102
, pp.
7
13
.
11.
Hynes
,
T. P.
, and
Greitzer
,
E. M.
, 1987, “
A Method for Assessing Effects of Circumferential Flow Distortion on Compressors Stability
,”
ASME J. Turbomach.
,
109
, pp.
371
379
.
12.
Moore
,
F. K.
, 1984, “
A Theory of Rotating Stall of Multistage Compressors, Parts I–III
,”
ASME J. Eng. Gas Turbines Power
,
106
, pp.
313
336
.
13.
Greitzer
,
E. M.
,
Mazzawy
,
R. S.
, and
Fulkerson
,
D. A.
, 1978, “
Flow Field Coupling Between Compression System Components in Asymmetric Flow
,”
ASME J. Eng. Power
,
100
, pp.
66
72
.
14.
Mazzawy
,
R. S.
, 1977, “
Multiple Segment Parallel Compressor Model for Circumferential Flow Distortion
,”
ASME J. Eng. Power
,
99
, pp.
288
296
.
15.
Longley
,
J. P.
, and
Greitzer
,
E. M.
, “
Inlet Distortion Effects in Aircraft Propulsion System Integration
,”
AGARD Lecture Series
,
1
.
16.
Dunham
,
J.
, 1965, “
Non-Axisymmetric Flows in Axial Flow Compressors
,”
Mech. Eng. Sci. Mono.
,
3
, pp.
1
32
.
17.
Hawthorne
,
W. R.
,
Mitchell
,
N. A.
, and
McCune
,
J. E.
, 1978, “
Non-Axisymmetric Flow Through Annular Actuator Disks: Inlet Distortion Problem
,”
ASME J. Eng. Power
,
100
, pp.
604
617
.
18.
Horlock
,
J. H.
, 1978,
Actuator Disk Theory. Discontinuities in Thermo-Fluid Dynamics
,
McGraw-Hill
,
New York
.
19.
Hsiao
,
E.
,
Naimi
,
M.
,
Lewis
,
J. P.
,
Dalbey
,
K.
,
Gong
,
Y.
, and
Tan
,
B.
, 2001, “
Actuator-Duct Model of Turbomachinery Components for Powered-Nacelle Vavier-Stokes Calculations
,”
ASME J. Propulsion Power
,
17-4
, pp.
919
927
.
20.
Xu
,
L.
, 2002, “
Assessing Viscous Body Forces for Unsteady Calculations
,” ASME Paper GT2002-30359.
21.
Hah
,
C.
,
Rabe
,
D. C.
,
Sullivan
,
T. J.
, and
Wadia
,
A. R.
, 1998, “
Effects of Inlet Distortion on the Flow Field in a Transonic Compressor Rotor
,”
ASME J. Turbomach.
,
120
, pp.
233
246
.
22.
Yao
,
J.
,
Gorrell
,
S. E.
, and
Wadia
,
A. R.
, 2007, “
A Time-Accurate CFD Analysis of Inlet Distortion Induced Swirl in Multistage Fans
,” AIAA Paper 2007-5059.
23.
Gorrell
,
S. E.
,
Yao
,
J.
, and
Wadia
,
A. R.
, 2008, “
High Fidelity URANS Analysis of Swirl Generation and Fan Response to Inlet Distortion
,” AIAA Paper 2008-4985.
24.
Yao
,
J.
,
Gorrell
,
S. E.
, and
Wadia
,
A. R.
, 2008, “
High-Fidelity Numerical Analysis of Per-Rev-Type Inlet Distortion Transfer in Multistage Fans—Part I: Simulations With Selected Blade Rows
,” ASME Paper GT2008-50812.
25.
Yao
,
J.
,
Gorrell
,
S. E.
, and
Wadia
,
A. R.
, 2008, “
High-Fidelity Numerical Analysis of Per-Rev-Type Inlet Distortion Transfer in Multistage Fans—Part II: Entire Component Simulation and Investigation
,” ASME Paper GT2008-50813.
26.
Strazisar
,
A. J.
,
Wood
,
J. R.
,
Hathaway
,
M. D.
, and
Suder
,
K. L.
, 1989, “
Laser Anemometer Measurements in a Transonic, Axial-Flow, Fan Rotor
,” NASA Technical Paper 2879.
27.
Cunnan
,
W. S.
,
Stevans
,
W.
, and
Urasek
,
D. C.
, 1978, “
Design and Performance of a 427-Meter-Per-Second-Tip-Speed Two-Stage Fan Having a 2.40 Pressure Ratio
,” NASA Technical Paper 1314.
28.
Urasek
,
D. C.
,
Gorrel
,
W. T.
, and
Cunnan
,
W. S.
, 1979, “
Performance of Two-Stage Fan Having Low-Aspect-Ratio, First-Stage Rotor Blading
,” NASA Technical Paper 1493.
29.
Hathaway
,
M. D.
, 1986, “
Unsteady Flows in a Single-Stage Transonic Axial-Flow Fan Stator Row
,” NASA Technical Memorandum 88929.
30.
Suder
,
K. L.
,
Hathaway
,
M. D.
,
Okiishi
,
T. H.
,
Strazisar
,
A. J.
, and
Adamczyk
,
J. J.
, 1987, “
Measurements of the Unsteady Flow Field Within the Stator Row of a Transonic Axial-Flow Fan. I—Measurement And Analysis Technique
,” NASA Technical Memorandum 88945.
31.
Hathaway
,
M. D.
,
Suder
,
K. L.
,
Okiishi
,
T. H.
,
Strazisar
,
A. J.
, and
Adamczyk
,
J. J.
, 1987, “
Measurements of the Unsteady Flow Field Within the Stator Row of a Transonic Axial-Flow Fan. II—Results And Discussion
,” NASA Technical Memorandum 88946.
32.
http://www.grc.nasa.gov/WWW/5810/w8.htm.
33.
Lapworth
,
B. L.
, 2004, “
HYDRA-CFD: A Framework for Collaborative CFD Development
,”
International Conference on Scientific and Engineering Computation IC-SEC
.
34.
Spalart
,
P. R.
, and
Allmaras
,
S. R.
, 1994, “
A One-Equation Turbulence Model for Aerodynamic Flows
,”
Rech. Aero
,
1
, pp.
5
21
.
35.
Vahdati
,
M.
,
Sayma
,
A. I.
,
Freeman
,
C.
, and
Imregun
,
M.
, 2005, “
On the Use of Atmospheric Boundary Conditions for Axial-Flow Compressors Stall Simulations
,”
ASME J. Turbomach.
,
127
, pp.
349
351
.
36.
Shahpar
,
S.
, and
Lapworth
,
B. L.
, 2003, “
PADRAM: Parametric Design and Rapid Meshing System for Turbomachinery Optimisation
,” ASME Paper GT2003-38698.
37.
Adamczyk
,
J. D.
, 1985, “
Model Equation for Simulating Flows in Multistage Turbomachinery
,”
ASME Paper 85-GT-226
.
You do not currently have access to this content.