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Research Papers

The Effect of an Eroded Leading Edge on the Aerodynamic Performance of a Transonic Fan Blade Cascade

[+] Author and Article Information
Alexander Hergt

German Aerospace Center (DLR),
Institute of Propulsion Technology,
Cologne 51147, Germany
e-mail: alexander.hergt@dlr.de

J. Klinner, W. Steinert, S. Grund, M. Beversdorff, A. Giebmanns, R. Schnell

German Aerospace Center (DLR),
Institute of Propulsion Technology,
Cologne 51147, Germany

1Corresponding author.

Contributed by the International Gas Turbine Institute (IGTI) of ASME for publication in the JOURNAL OF TURBOMACHINERY. Manuscript received July 4, 2014; final manuscript received July 10, 2014; published online September 16, 2014. Editor: Ronald Bunker.

J. Turbomach 137(2), 021006 (Sep 16, 2014) (11 pages) Paper No: TURBO-14-1112; doi: 10.1115/1.4028215 History: Received July 04, 2014; Revised July 10, 2014

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.

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References

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. [CrossRef]
Siller, U., Voß, C., and Nicke, E., 2009, “Automated Multidiciplinary Optimization of a Transonic Axial Compressor,” AIAA Paper No. 2009-863. [CrossRef]
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.
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.
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. [CrossRef]
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. [CrossRef]
Goodhand, M. N., and Miller, R. J., 2011, “Compressor Leading Edge Spikes: A New Performance Criterion,” ASME J. Turbomach., 133(2), p. 021006. [CrossRef]
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. [CrossRef]
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.
Denton, J. D., 1993, “Loss Mechanisms in Turbomachines,” ASME J. Turbomach., 115(4), pp. 621–656. [CrossRef]
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. [CrossRef]
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.
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. [CrossRef]
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.
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. [CrossRef]
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.
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.
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.
Steinert, W., Fuchs, R., and Starken, H., 1992, “Inlet Flow Angle Determination of Transonic Compressor Cascade,” ASME J. Turbomach., 114(3), pp. 487–493. [CrossRef]
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.
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. [CrossRef]
Schodl, R., 1989, “Laser Two Focus Techniques,” Measurement Techniques in Aerodynamics (VKI Lecture Series 1989-05), von Karman Institute, Rhode-St-Genese, Belgium.
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.
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. [CrossRef]
Steinert, W., and Starken, H., 1996, “Off-Design Transition and Separation Behavior of a CDA Cascade,” ASME J. Turbomach., 118(2), pp. 204–210. [CrossRef]
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.
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.
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. [CrossRef]
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. [CrossRef]
Cumpsty, N. A., 2004, Compressor Aerodynamics, Krieger Publishing Company, Malabar, FL.
Scholz, N., 1977, Aerodynamics of Cascades, AGARDograph AG-220, AGARD, London.

Figures

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Fig. 1

Transonic fan blade cascade with planar endwall (five of six blades)

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Fig. 2

Fan blade with OLE and BLE

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Fig. 3

Cross section of the DLR transonic cascade wind tunnel

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Fig. 4

Cascade parameters, definition of MPs and boundary layer suction design

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Fig. 5

Multiblock grid topology

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Fig. 6

Experimental loss—inflow angle characteristics of the datum and the BLE cascade (M1 = 1.25)

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Fig. 7

Experimental shock loss—inflow angle characteristics of the datum and the BLE cascade (M1 = 1.25)

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Fig. 8

Isentropic Mach number distribution of the datum cascade at OP 1 and OP 2 (M1 = 1.25, AVDR ≈ 1.12)

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Fig. 9

Inflow angle distribution of the datum and the BLE cascade at OP 1 and OP 2 (M1 = 1.25, AVDR ≈ 1.12), (L2F-MP at midspan)

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Fig. 10

Loss distribution in the wake behind the datum and the BLE cascade at OP 1 and OP 2 (M1 = 1.25, AVDR ≈ 1.12) (midspan)

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Fig. 11

Schlieren pattern (top), schematic diagram of the shock position (middle), PIV-measurement at the leading edge (bottom) at OP 1 of the datum cascade

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Fig. 12

Schlieren pattern (top), schematic diagram of the shock position (middle), PIV-measurement at the leading edge (bottom) at OP 1 of the BLE cascade

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Fig. 13

Numerical Mach number distribution at the leading edge of the datum cascade at OP 1

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Fig. 14

Numerical Mach number distribution at the leading edge of the BLE cascade at OP 1

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Fig. 15

Schlieren pattern (top), schematic diagram of the shock position (middle), PIV-measurement at the leading edge (bottom) at OP 2 of the datum cascade

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Fig. 16

Schlieren pattern (top), schematic diagram of the shock position (middle), PIV-measurement at the leading edge (bottom) at OP 2 of the BLE cascade

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Fig. 17

Power density spectra of the shock motion at OP 1 and OP 2

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Fig. 18

Shock fluctuation around the averaged shock position along xn at OP 2

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Fig. 19

Adiabatic wall temperature estimated for the laminar and turbulent boundary layer at OP 1 and OP 2 (liquid crystal color spectrum on the left hand side)

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Fig. 20

Liquid crystal measurement on the blade suction side of the datum (left) and the BLE cascade (right) at OP 1

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Fig. 21

Liquid crystal measurement on the blade suction side of the datum (left) and the BLE cascade (right) at OP 2

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Fig. 22

Performance map of the original fan compared to the fan with BLE (left) and reshaped leading edge (right) [6]

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