Especially at transonic flow conditions the leading edge shape influences the performance of a fan profile. At the same time the leading edge of a fan profile is highly affected by erosion during operation. This erosion leads to a deformation of the leading edge shape and a reduction of the chord length. In the present experimental and numerical study, the aerodynamic performance of an original fan profile geometry is compared to an eroded fan profile with a blunt leading edge (BLE) and a chord length reduced by about 1%. The experiments are performed at a linear fan blade cascade in the Transonic Cascade Wind Tunnel of DLR in Cologne. The inflow Mach number during the tests is 1.25 and the Reynolds number 1.5 × 106. All tests are carried out at a low inflow turbulence level of 0.8%. The results of the investigation show that losses are increased over the whole operating range of the cascade. At the aerodynamic design point (ADP) the losses raise by 25%. This significant loss increase can be traced back to the increase of the shock losses at the leading edge. The change in shock structure is investigated and described in detail by means of particle image velocimetry (PIV) measurements and Schlieren imaging. Additionally, the unsteady fluctuation of the shock position is measured by a high-speed shadowgraphy. Then the frequency range of the fluctuation is obtained by a Fourier analysis of the time resolved shock position. Furthermore, liquid crystal measurements are performed in order to analyze the influence of the leading edge shape on the development of the suction side boundary layer. The results show that for the original fan blade the transition occurs at the shock position on the blade suction side by a separation bubble whereas the transition onset is shifted upstream for the fan blade with the BLE.

References

References
1.
Kerrebrock
,
J. L.
,
Epstein
,
A. H.
,
Merchant
,
A. A.
,
Guenette
,
G. R.
,
Parker
,
D.
,
Omnee
,
J.-F.
,
Neumayer
,
F.
,
Adamczyk
,
J. J.
, and
Shabbir
,
A.
,
2008
, “
Design and Test of an Aspirated Counter-Rotating Fan
,”
ASME J. Turbomach.
,
130
(
2
), p.
021004
.10.1115/1.2776951
2.
Siller
,
U.
,
Voß
,
C.
, and
Nicke
,
E.
,
2009
, “
Automated Multidiciplinary Optimization of a Transonic Axial Compressor
,”
AIAA
Paper No. 2009-863.10.2514/6.2009-863
3.
Lengyel
,
T.
,
Schmidt
,
T.
,
Voß
,
C.
, and
Nicke
,
E.
,
2009
, “
Design of a Counter Rotating Fan—An Aircraft Engine Technology to Reduce Noise and CO2-Emissions
,”
19th ISABE Conference
,
Montreal, Canada
, Sept. 7–11, ISABE Paper No. 2009-1267.
4.
Lengyel
,
T.
,
Nicke
,
E.
,
Rüd
,
K.-P.
, and
Schaber
,
R.
,
2011
, “
Optimization and Examination of a Counter Rotating Fan Stage—The Possible Improvement of the Efficiency Compared With a Single Rotating Fan
,”
20th ISABE Conference
,
Gothenburg, Sweden
, Sept. 12–16, ISABE Paper No. 2011-1232.
5.
Lengyel-Kampmann
,
T.
,
Bischoff
,
A.
,
Meyer
,
R.
, and
Nicke
,
E.
,
2012
, “
Design of an Economical Counter Rotating Fan—Comparison of the Calculated and Measured Steady and Unsteady Results
,”
ASME
Paper No. GT2012-69587. 10.1115/GT2012-69587
6.
Giebmanns
,
A.
,
Schnell
,
R.
,
Steinert
,
W.
,
Hergt
,
A.
,
Nicke
,
E.
, and
Werner-Spatz
,
C.
,
2012
, “
Analyzing and Optimizing Geometrically Degraded Transonic Fan Blades by Means of 2D and 3D Simulations and Cascade Measurements
,”
ASME
Paper No. GT2012-69064. 10.1115/GT2012-69064
7.
Goodhand
,
M. N.
, and
Miller
,
R. J.
,
2011
, “
Compressor Leading Edge Spikes: A New Performance Criterion
,”
ASME J. Turbomach.
,
133
(
2
), p.
021006
.10.1115/1.4000567
8.
Goodhand
,
M. N.
,
Miller
,
R. J.
, and
Lung
,
H. W.
,
2012
, “
The Sensitivity of 2D Compressor Incidence Range to In-Service Geometrie Variation
,”
ASME
Paper No. GT2012-68633. 10.1115/GT2012-68633
9.
Broichhausen
,
K. D.
, and
Gallus
,
H. E.
,
1986
, “
Influence of Shock and Boundary Layer Losses on the Performance of Highly Loaded Supersonic Axial Flow Compressors
,”
Transonic and Supersonic Phenomena in Turbomachines
, Proceedings of the Propulsion and Energetics 68th Specialists' Meeting (AGARD-CP-401), Munich, Sept. 10–12,
AGARD, Munich
, pp.
9-1
9-14
.
10.
Denton
,
J. D.
,
1993
, “
Loss Mechanisms in Turbomachines
,”
ASME J. Turbomach.
,
115
(
4
), pp.
621
656
.10.1115/1.2929299
11.
Reid
,
L.
, and
Urasek
,
D. C.
,
1973
, “
Experimental Evaluation of the Effects of a Blunt Leading Edge on the Performance of a Transonic Rotor
,”
ASME J. Eng. Power
,
95
(
3
), pp.
199
204
.10.1115/1.3445723
12.
Schreiber
,
H. A.
, and
Starken
,
H.
,
1981
, “
Evaluation of Blade Element Performance of Compressor Rotor Blade Cascades in Transonic and Low Supersonic Flow Range
,”
5th International Symposium on Air Breathing Engines
,
Bangalore, India
, Feb. 16–22, pp.
67-1
67-9
.
13.
Schreiber
,
H. A.
, and
Starken
,
H.
,
1984
, “
Experimental Cascade Analysis of a Transonic Compressor Rotor Blade Section
,”
ASME J. Eng. Gas Turbines Power
,
106
(
2
), pp.
288
294
.10.1115/1.3239561
14.
Schreiber
,
H. A.
,
1986
, “
Experimental Investigation on Shock Losses of Transonic and Supersonic Compressor Cascades
,”
Transonic and Supersonic Phenomena in Turbomachines
, Proceedings of the Propulsion and Energetics 68th Specialists' Meeting (AGARD-CP-401), Munich, Sept. 10–12,
AGARD, Munich, Paper No. AGARD-CP-401
, pp.
11-1
11-15
.
15.
Schreiber
,
H. A.
, and
Starken
,
H.
,
1992
, “
An Investigation of a Strong Shock-Wave Turbulent Boundary Layer Interaction in a Supersonic Compressor Cascade
,”
ASME J. Turbomach.
,
114
(
3
), pp.
494
503
.10.1115/1.2929170
16.
Schreiber
,
H. A.
,
1996
, “
Shock-Wave Turbulent Boundary Layer Interaction in a Highly Loaded Transonic Fan Blade Cascade
,”
85th AGARD-PEP Symposium on Loss Mechanisms and Unsteady Flows in Turbomachines
,
(AGARD-CP-571), Derby, UK
, May 8–12, pp.
17-1
17-14
.
17.
Tweedt
,
T. L.
,
Schreiber
,
H. A.
, and
Starken
,
H.
,
1988
, “
Experimental Investigation of the Performance of a Supersonic Compressor Cascade
,”
ASME Turbo Expo
,
Amsterdam, Netherlands
, June 6–9, ASME Paper No. 88-GT-306.
18.
Schreiber
,
H. A.
,
Starken
,
H.
, and
Steinert
,
W.
,
1993
, “
Transonic and Supersonic Cascades
,”
AGARDOgraph 328 on Advanced Methods for Cascade Testing
, pp.
35
72
, AGARD, Munich.
19.
Steinert
,
W.
,
Fuchs
,
R.
, and
Starken
,
H.
,
1992
, “
Inlet Flow Angle Determination of Transonic Compressor Cascade
,”
ASME J. Turbomach.
,
114
(
3
), pp.
487
493
.10.1115/1.2929169
20.
Schimming
,
P.
,
1976
, “
Experimental Investigation of Supersonic Inflow of Compressor Cascade by the Laser-2-Focus Method
,”
Symposium of Measuring Techniques in Transonic and Supersonic Cascade Flow
, Lausanne, Switzerland, Nov. 18–19.
21.
Schodl
,
R.
,
1980
, “
A Laser-Two-Focus (L2F) Velocimeter for Automatic Flow Vector Measurements in the Rotating Components of Turbomachines
,”
ASME J. Fluids Eng.
,
102
(
4
), pp.
412
419
.10.1115/1.3240713
22.
Schodl
,
R.
,
1989
, “
Laser Two Focus Techniques
,” Measurement Techniques in Aerodynamics (VKI Lecture Series 1989-05), von Karman Institute, Rhode-St-Genese, Belgium.
23.
Klinner
,
J.
,
Hergt
,
A.
,
Beversdorff
,
M.
, and
Willert
,
C.
,
2012
, “
Visualization and PIV Measurements of the Transonic Flow Around the Leading Edge of an Eroded Fan Airfoil
,”
16th International Symposium on Applications of Laser Techniques to Fluid Mechanics
,
Lisbon, Portugal
, July 9–12.
24.
Mee
,
D. J.
,
Walton
,
T. W.
,
Harrison
,
S. B.
, and
Jones
,
T.
,
1991
, “
A Comparison of Liquid Crystal Techniques for Transition Detection
,”
AIAA
Paper No. 91-0062. 10.2514/6.1991-62
25.
Steinert
,
W.
, and
Starken
,
H.
,
1996
, “
Off-Design Transition and Separation Behavior of a CDA Cascade
,”
ASME J. Turbomach.
,
118
(
2
), pp.
204
210
.10.1115/1.2836627
26.
Schreiber
,
H. A.
,
1976
, “
Comparison Between Flows in Cascades and Rotors in the Transonic Range
,” Transonic Blade-to-Blade Flows in Axial Turbomachinery (VKI Lecture Series 84), von Karman Institute, Rhode Saint Genése, Belgium.
27.
Schreiber
,
H. A.
, and
Starken
,
H.
,
1981
, “
On the Definition of the Axial Velocity Density Ratio in Theoretical and Experimental Cascade Investigation
,”
Symposium on Measuring Techniques in Transonic and Supersonic Flow in Cascades and Turbomachines
,
Lyon, France
, Oct. 15–16.
28.
Willert
,
C.
,
Mitchell
,
D. M.
, and
Soria
,
J.
,
2012
, “
An Assessment of High-Power Light-Emitting Diodes for High Frame Rate Schlieren Imaging
,”
Exp. Fluids
,
53
(
2
), pp.
413
421
.10.1007/s00348-012-1297-1
29.
Schreiber
,
H. A.
,
Steinert
,
W.
, and
Kuesters
,
B.
,
2002
, “
Effects of Reynolds Numbers and Free-Stream Turbulence on Boundary Layer Transition in a Compressor Cascade
,”
ASME J. Turbomach.
,
124
(
1
), pp.
1
9
.10.1115/1.1413471
30.
Cumpsty
,
N. A.
,
2004
,
Compressor Aerodynamics
,
Krieger Publishing Company
, Malabar, FL.
31.
Scholz
,
N.
,
1977
,
Aerodynamics of Cascades
,
AGARDograph AG-220, AGARD
, London.
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