Details
| Original language | English |
|---|---|
| Title of host publication | Structures and Dynamics |
| Subtitle of host publication | Aerodynamics Excitation and Damping; Bearing and Seal Dynamics; Emerging Methods in Engineering Design, Analysis, and Additive Manufacturing |
| Publisher | American Society of Mechanical Engineers(ASME) |
| ISBN (electronic) | 9780791888025 |
| Publication status | Published - 28 Aug 2024 |
| Event | 69th ASME Turbo Expo 2024: Turbomachinery Technical Conference and Exposition, GT 2024 - London, United Kingdom (UK) Duration: 24 Jun 2024 → 28 Jun 2024 |
Publication series
| Name | Proceedings of the ASME Turbo Expo |
|---|---|
| Volume | 10A |
Abstract
During the design process of turbomachinery, it is often not possible to use aerodynamically optimal designs due to aeroelastic constraints. The design choices are limited by possible structural failure, which can be caused by high vibration amplitudes, for example due to self-excited vibrations (flutter) or forced response. In particular, the modal damping has an important impact on these phenomena. In the absence of frictional contacts, damping is mainly created by aerodynamics. In this paper, the influence of additional damping created by the rotor bearing on the total damping and on forced vibrations will be investigated. This influence becomes relevant when blade vibrations with nodal diameters 1 and -1 couple with the shaft vibrations. The coupling is caused by a structural dynamic interaction of these two components. To investigate the blade-shaft coupling, a simulation process is set up to best represent the physical effects during operation. This simulation process is essentially based on a full structural dynamic model of the blisk-shaft assembly and a harmonic balance CFD model to account for the aeroelastic effects. In addition, mistuning identification is performed based on an experimental modal analysis at standstill. All results are incorporated into a structural reduced order model that calculates the vibrational behavior of the blading. These results are compared to damping determined during operation using an acoustic excitation system and measured forced frequency responses. The numerical results agree well with the experimental results, i.e. within the measurement uncertainty, both with respect to the damping and the mistuned frequency responses. Furthermore, the blade-shaft coupling results in significant changes of the eigenfrequencies and damping. As a consequence, damping increases by up to twelve times when taking the coupling into account. This reduces amplitudes by a factor of nine for the mistuned blade responses. Consequently, higher structural safety factors can be achieved by taking the blade-shaft coupling into account so that the remaining potentials in the aerodynamic design could be better exploited.
Keywords
- Aeroelasticity, Compressor, Structural dynamics
ASJC Scopus subject areas
- Engineering(all)
- General Engineering
Cite this
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Structures and Dynamics : Aerodynamics Excitation and Damping; Bearing and Seal Dynamics; Emerging Methods in Engineering Design, Analysis, and Additive Manufacturing. American Society of Mechanical Engineers(ASME), 2024. V10AT21A005 (Proceedings of the ASME Turbo Expo; Vol. 10A).
Research output: Chapter in book/report/conference proceeding › Conference contribution › Research › peer review
}
TY - GEN
T1 - Aeroelastic influence of blade-shaft coupling in a 1 1/2 stage axial compressor
AU - Maroldt, Niklas
AU - Seume, Joerg R.
PY - 2024/8/28
Y1 - 2024/8/28
N2 - During the design process of turbomachinery, it is often not possible to use aerodynamically optimal designs due to aeroelastic constraints. The design choices are limited by possible structural failure, which can be caused by high vibration amplitudes, for example due to self-excited vibrations (flutter) or forced response. In particular, the modal damping has an important impact on these phenomena. In the absence of frictional contacts, damping is mainly created by aerodynamics. In this paper, the influence of additional damping created by the rotor bearing on the total damping and on forced vibrations will be investigated. This influence becomes relevant when blade vibrations with nodal diameters 1 and -1 couple with the shaft vibrations. The coupling is caused by a structural dynamic interaction of these two components. To investigate the blade-shaft coupling, a simulation process is set up to best represent the physical effects during operation. This simulation process is essentially based on a full structural dynamic model of the blisk-shaft assembly and a harmonic balance CFD model to account for the aeroelastic effects. In addition, mistuning identification is performed based on an experimental modal analysis at standstill. All results are incorporated into a structural reduced order model that calculates the vibrational behavior of the blading. These results are compared to damping determined during operation using an acoustic excitation system and measured forced frequency responses. The numerical results agree well with the experimental results, i.e. within the measurement uncertainty, both with respect to the damping and the mistuned frequency responses. Furthermore, the blade-shaft coupling results in significant changes of the eigenfrequencies and damping. As a consequence, damping increases by up to twelve times when taking the coupling into account. This reduces amplitudes by a factor of nine for the mistuned blade responses. Consequently, higher structural safety factors can be achieved by taking the blade-shaft coupling into account so that the remaining potentials in the aerodynamic design could be better exploited.
AB - During the design process of turbomachinery, it is often not possible to use aerodynamically optimal designs due to aeroelastic constraints. The design choices are limited by possible structural failure, which can be caused by high vibration amplitudes, for example due to self-excited vibrations (flutter) or forced response. In particular, the modal damping has an important impact on these phenomena. In the absence of frictional contacts, damping is mainly created by aerodynamics. In this paper, the influence of additional damping created by the rotor bearing on the total damping and on forced vibrations will be investigated. This influence becomes relevant when blade vibrations with nodal diameters 1 and -1 couple with the shaft vibrations. The coupling is caused by a structural dynamic interaction of these two components. To investigate the blade-shaft coupling, a simulation process is set up to best represent the physical effects during operation. This simulation process is essentially based on a full structural dynamic model of the blisk-shaft assembly and a harmonic balance CFD model to account for the aeroelastic effects. In addition, mistuning identification is performed based on an experimental modal analysis at standstill. All results are incorporated into a structural reduced order model that calculates the vibrational behavior of the blading. These results are compared to damping determined during operation using an acoustic excitation system and measured forced frequency responses. The numerical results agree well with the experimental results, i.e. within the measurement uncertainty, both with respect to the damping and the mistuned frequency responses. Furthermore, the blade-shaft coupling results in significant changes of the eigenfrequencies and damping. As a consequence, damping increases by up to twelve times when taking the coupling into account. This reduces amplitudes by a factor of nine for the mistuned blade responses. Consequently, higher structural safety factors can be achieved by taking the blade-shaft coupling into account so that the remaining potentials in the aerodynamic design could be better exploited.
KW - Aeroelasticity
KW - Compressor
KW - Structural dynamics
UR - http://www.scopus.com/inward/record.url?scp=85204383934&partnerID=8YFLogxK
U2 - 10.1115/GT2024-124275
DO - 10.1115/GT2024-124275
M3 - Conference contribution
AN - SCOPUS:85204383934
T3 - Proceedings of the ASME Turbo Expo
BT - Structures and Dynamics
PB - American Society of Mechanical Engineers(ASME)
T2 - 69th ASME Turbo Expo 2024: Turbomachinery Technical Conference and Exposition, GT 2024
Y2 - 24 June 2024 through 28 June 2024
ER -