Subproject C6 Aeroelasticity of Multi-Stage Axial Compressors

The aeroelasticity of mistuned axial compressors with multiple stages is investigated. By using an improved simulation methodology, the influence of regeneration on the vibration behavior of compressor blisks is analyzed. The focus is on the structural and aerodynamic coupling of compressor blades between different stages.

MOTIVATION AND OBJECTIVES

Axial compressor rig at the Institute of Turbomachinery and Fluid Dynamics

In modern aircraft engines blade integrated disks (Blisks) are used more and more, because they permit a high pressure ratio per stage while being lightweight. Due to their low mechanical damping, they are highly sensitive to vibration excitation. Geometrical variances caused by wear and regeneration have a significant influence on the vibrational behavior.  The main goal is therefore the prediction of the operational vibrational behavior of multistage compressors, while considering these variances. The results enable accurate part life predictions.

RESULTS

The current project results from the fusion of the sub-projects C6 “Aeroelasticity of Compressor Blisks” and C3 “Regeneration-induced Mistuning”. In the sub-project C6, the influence of (regeneration-induced) geometric variances on the vibrational behavior of an axial compressor blisk was analyzed, focusing on blend repairs. This influence was quantified in simulations, and shown in measurements using a blisk geometry designed for this purpose. The calculated aerodynamic damping was used in the sub-project C3 to enable more accurate simulations of the vibrational behavior. In this case, mistuning was focused – deviations from the cyclic symmetry. A model order reduction method developed earlier was extended to enable the consideration of deviations in the disk segments.

CURRENT RESEARCH AND OUTLOOK

Currently there are two main goals: Extending the models to include multiple stages, and  a direct integration of geometric variances into the reduced order model. In multi-stage models, the vibration excitation and response contain multiple harmonics which has to be considered. The stator angle of attack (of the stator vanes) is varied  in order to realize this kind of excitation in the axial compressor (at TFD). In the end an integrated simulation method is developed that, together with the sub-projects B4 and C5, enables fast and accurate part life prediction for axial compressors. This represents an important contribution to the decision on the regeneration path.


PUBLICATIONS

International Conference Paper, peer-reviewed

  • Keller, C.; Kellersmann, A.; Friedrichs, J.; Seume, J. R. (2017): Influence of Geometric Imperfections on Aerodynamic and Aeroelastic Behavior of a Compressor BliskIn: Proceedings of ASME Turbo Expo 2017, Charlotte, USA, GT2017-63556
  • Schwerdt, L.; Berger, R.; Keller, C.; Seume, J.; Rolfes, R.; Panning-von Scheidt, L.; Wallaschek, J. (2017): Influence of Blade Repairs on Compressor Blisk Vibration considering Aerodynamic Damping and MistuningGPPS (Hg.): Proceedings of Global Power and Propulsion Society Conference. Shanghai
  • Willeke, S.; Keller, C.; Panning-von Scheidt, L.; Seume, J.; Wallaschek, J. (2017): Reduced Order Modeling of Mistuned Bladed Disks Considering Aerodynamic Coupling and Mode Family InteractionIn: Proceedings of 12th European Conference on Turbomachinery Fluid Dynamics & Thermodynamics (ETC12), April 3-7, Stockholm, Sweden, ETC2017-242
  • Hurfar, C. Mandanna; Keller, C.; Mumcu, A.; Seume, J. R. (2016): An Acoustic Excitation System for the Generation of Turbomachinery Specific Sound Fields: Part II - Experimental VerificationIn: Proceedings of the ASME Turbo Expo 2016, Seoul, South Korea
  • Mumcu, A.; Keller, C.; Hurfar, C. Mandanna; Seume, J. R. (2016): An Acoustic Excitation System for the Generation of Turbomachinery Specific Sound Fields: Part I - Design and MethodologyIn: Proceedings of the ASME Turbo Expo 2016, Seoul, South Korea
  • Keller, C.; Willeke, T.; Burrafato, S.; Seume, J. R. (2015): Design Process of a 1.5-Stage Axial Compressor for Experimental Flutter InvestigationsIn: Proceedings of the International Gas Turbine Congress 2015, Tokyo, Japan, S. 1130–1139

International Conference Paper, not peer-reviewed

  • Bittner, S. L.; Keller, C.; Meinzer, C. E.; Seume, J. R. (2018): Experimental Validation of a Forced Response Analysis Using a Time-Linearized Method2018 AIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference, AIAA SciTech Forum
    DOI: 10.2514/6.2018-0461
All publications of the Collaborative Research Centre

SUBPROJECT LEADER

Prof. Dr.-Ing. Jörg Seume
Address
An der Universität 1
30823 Garbsen, Raum 315
Address
An der Universität 1
30823 Garbsen, Raum 315
Dr.-Ing. Lars Panning-von Scheidt genannt Weschpfennig