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Research Papers

Application of the Modal Approach for Prediction of Forced Response Amplitudes for Fan Blades

[+] Author and Article Information
Franziska Eichner

Institute for Aeroelasticity DLR,
German Aerospace Center,
Bunsenstr. 10,
Göttingen 37073, Germany
e-mail: Franziska.Eichner@dlr.de

Joachim Belz

Institute for Aeroelasticity DLR,
German Aerospace Center,
Bunsenstr. 10,
Göttingen 37073, Germany
e-mail: Joachim.Belz@dlr.de

1Corresponding author.

Manuscript received June 26, 2018; final manuscript received August 21, 2018; published online October 16, 2018. Editor: Jerzy T. Sawicki.

J. Eng. Gas Turbines Power 141(3), 031019 (Oct 16, 2018) (8 pages) Paper No: GTP-18-1360; doi: 10.1115/1.4041453 History: Received June 26, 2018; Revised August 21, 2018

Forced response is the main reason for high cycle fatigue in turbomachinery. Not all resonance points in the operating range can be avoided especially for low order excitation. For highly flexible carbon fiber reinforced polymer (CFRP) fans, an accurate calculation of vibration amplitudes is required. Forced response analyses were performed for blade row interaction and boundary layer ingestion (BLI). The resonance points considered were identified in the Campbell diagram. Forced response amplitudes were calculated using a modal approach and the results are compared to the widely used energy method. For the unsteady simulations, a time-based linearization of the unsteady Reynolds average Navier–Stokes equations were applied. If only the resonant mode was considered, the forced response amplitude from the modal approach was confirmed with the energy method. Thereby, forced response due to BLI showed higher vibration amplitudes than for blade row interaction. The impact of modes which are not in resonant to the total deformation were investigated by using the modal approach, which so far only considers one excitation order. A doubling of vibrational amplitude was shown in the case of blade row interaction for higher rotational speeds. The first and third modeshapes as well as modes with similar natural frequencies were identified as critical cases. The behavior in the vicinity of resonance shows high vibration amplitudes over a larger frequency range. This is also valid for high modes with many nodal diameters, which have a greater risk of critical strain.

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References

Kielb, R. , and Chiang, H. , 1992, “Recent Advancements in Turbomachinery Forced Response Analyses,” AIAA Paper No. AIAA-92-0012.
Korakianitis, T. , 1992, “On the Prediction of Unsteady Forces on Gas Turbine Blades—Part 1: Description of the Approach,” ASME J. Turbomach., 114(1), pp. 114–122. [CrossRef]
Korakianitis, T. , 1992, “On the Prediction of Unsteady Forces on Gas Turbine Blades—Part 2: Analysis of the Results,” ASME J. Turbomach., 114(1), pp. 123–131. [CrossRef]
Moffatt, S. , and He, L. , 2003, “Blade Forced Response Prediction for Industrial Gas Turbine—Part I: Methodologies,” ASME Paper No. GT2003-38640.
Ning, W. , Moffatt, S. , Li, Y. , and Wells, R. G. , 2003, “Blade Forced Response Prediction for Industrial Gas Turbine—Part II: Verification and Application,” ASME Paper No. GT2003-38642.
Vasanthakumar, P. , and Ebel, P.-B. , 2012, “Forced Response Analysis of a Transonic Fan,” ASME Paper No. GT2012-69867.
Blocher, M. , and Gómez Fernández, I. E. , 2014, “Time-Linearized Forced Response Analysis of a Counter Rotating Fan—Part I: Theoretical Concept of a Fully Time-Linear Forced Response Analysis,” ASME Paper No. GT2014-25833.
Gómez Fernández, I. E. , and Blocher, M. , 2014, “Time-Linearized Forced Response Analysis of a Counter Rotating Fan—Part II: Analysis of the DLR CRISP2 Model,” ASME Paper No. GT2014-25838.
Petrov, E. D. , Mare, L. , Hennings, H. , and Elliot, R. , 2009, “Forced Response of Mistuned Bladed Discs in Gas Flow: A Comparative Study of Predictions and Full-Scale Experimental Results,” ASME Paper No. GT2009-59632.
Aulich, A.-L. , Görke, D. , Blocher, M. , Nicke, E. , and Kocian, F. , 2013, “Multidisciplinary Automated Optimization Strategy on a Counter Rotating Fan,” ASME Paper No. GT2013-94259.
Schuff, M. , Lengyel-Kampmann, T. , and Forsthofer, N. , 2017, “Influence of the Steady Deformation on Numerical Flutter Prediction for Highly Loaded and Flexible Fan Blades,” ASME Paper No. GT2017-64027.
Belz, J. , and Irretier, H. , 1998, “The Use of Modal Parameters for the Identification of the Unbalance Distribution of Elastic Rotors,” Fifth International Conference on Rotor Dynamics, pp. 679–694.
Lane, F. , 1956, “System Mode Shapes in the Flutter of Compressor Blade Rows,” ASME J. Turbomach., 23(1), pp. 54–66.
Carta, F. , 1967, “Coupled Blade-Disk-Shroud Flutter Instabilities in Turbojet Engine Rotors,” J. Eng. Power, 83(3), pp. 419–426.
Görke, D. , Le Denmat, A.-L. , Schmidt, T. , Kocian, F. , and Nicke, E. , 2012, “Aerodynamic and Mechanical Optimization of CF/PEEK Blades of a Counter Rotating Fan,” ASME Paper No. GT2012-68797.
Blocher, M. , and Aulich, A.-L. , 2013, “Flutter Susceptibility Approximation Via Curve Fitting and MAC-Analysis in an Automated Optimization Design Process,” ASME Paper No. GT2013-94577.
Lengyel-Kampmann, T. , Voß, C. , Nicke, E. , Rüd, K.-P. , and Schaber, R. , 2014, “Generalized Optimization of Counter-Rotating and Single-Rotating Fans,” ASME Paper No. GT2014-26008.
Frey, C. , Ashcroft, G. , Kersken, H.-P. , and Schönweitz, D. , 2017, “Simulation of Indexing and Clocking With Harmonic Balance,” 12th European Conference on Turbomachinery and Fluid Dynamics, Stockholm, Sweden, Apr. 3–7, Paper No. ETC2017-135.
Kersken, H.-P. , Frey, C. , Voigt, C. , and Ashcroft, G. , 2010, “Time-Linearized and Time-Accurate 3D RANS Methods for Aeroelastic Analysis in Turbomachinery,” ASME Paper No. GT2010-22940.
May, M. , and Grüber, B. , 2011, “Reliability of Time-Linearized Flutter Predictions Near the Surge Line,” Ninth European Conference on Turbomachinery Fluid Dynamics and Thermodynamics, Istanbul, Turkey, Mar. 21–25, Paper No. ETC2011-208.
Forsthofer, N. , and Reiber, C. , 2016, “Structural Mechanic and Aeroelastic Approach for Design and Simulation of CFRP Fan Blades,” Deutscher Luft- Und Raumfahrtkongress 2016, Braunschweig, Germany.
Reiber, C. , and Blocher, M. , 2017, “Potential of Aeroelastic Tailoring to Improve Flutter Stability of Turbomachinery Compressor Blades,” 12th European Conference on Turbomachinery and Fluid Dynamics, Stockholm, Sweden, Apr. 3–7, Paper No. ETC2017-180. https://elib.dlr.de/113270/1/Paper_Reiber_SUBID180_revised.pdf

Figures

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Fig. 1

Counter-rotating integrated shrouded propfan—CRISP2

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Fig. 2

Forced response methodology: modal approach

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Fig. 3

Forced response methodology: energy method

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Fig. 4

Forced response amplitude through energy method

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Fig. 5

Generic BLI: (a) flow-Condition at Inlet and (b) fourier decomposition of BLI

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Fig. 6

Computational fluid dynamics mesh

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Fig. 7

Campbell diagram of the first rotor

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Fig. 8

Deformation due to blade row interaction: (a) 82% rotational speed, (b) 88% rotational speed, (c) 92% rotational speed, and (d) 102% rotational speed

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Fig. 9

Blade row interaction: (a) aerodynamic excitation and (b) aerodynamic damping

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Fig. 10

Deformation due to BLI: (a) 50% rotational speed, EO 02; (b) 52% rotational speed, EO 08; (c) 55% rotational speed, EO 05; and (d) 75% rotational speed, EO 04

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Fig. 11

Boundary layer ingestion: (a) aerodynamic excitation and (b) aerodynamic damping

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