Details
| Original language | English |
|---|---|
| Article number | 121011 |
| Journal | Journal of turbomachinery |
| Volume | 142 |
| Issue number | 12 |
| Early online date | 2 Dec 2020 |
| Publication status | Published - Dec 2020 |
Abstract
Aerodynamic damping is the key parameter to determine the stability of vibrating blade rows in turbomachinery design. Both, the assessments of flutter and forced response vibrations need an accurate estimate of the aerodynamic damping to reduce the risk of high cycle fatigue that may result in blade loss. However, only very few attempts have been made to measure the aerodynamic damping of rotating blade rows experimentally under realistic operating conditions, but always with friction damping being present. This study closes the gap by providing an experiment in which a turbine blisk is used to eliminate friction damping at the blade roots and thereby isolate aerodynamic damping. The blades are excited acoustically and the resulting nodal diameter modes are measured using an optical tip-Timing system in order to realize a fully non-intrusive setup. The measured vibration data are fitted to a single degree-of-freedom model (SDOF) to determine the aerodynamic damping. The results are in good accordance with the time-linearized CFD simulation. It is observed, however, that not only the sweep rate of the acoustic excitation but also the variation of the rotational frequency during the sweep excitation, and the excitation frequency influence the apparent damping.
Keywords
- Aeromechanical instabilities, Measurement techniques, Turbine blade and measurement advancements
ASJC Scopus subject areas
- Engineering(all)
- Mechanical Engineering
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In: Journal of turbomachinery, Vol. 142, No. 12, 121011, 12.2020.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Experimental and Numerical Quantification of the Aerodynamic Damping of a Turbine Blisk
AU - Meinzer, Christopher E.
AU - Seume, Joerg R.
N1 - Funding Information: The numerical and experimental investigations are conducted as part of the joint research program COORETECturbo-2020 in AG Turbo. The work is supported by the Federal Ministry for Economic Affairs and Energy (BMWi) and SIEMENS AG under file number 03ET2013A and 03ET2012A on the basis of a resolution of the German Parliament. The authors gratefully acknowledge AG Turbo and SIEMENS AG for their support and permission to publish this paper. Furthermore, the authors thank the DLR Institute of Propulsion Technology for providing TRACE and the Leibniz Universität Hannover IT Services (LUIS) for the computational resources provided.
PY - 2020/12
Y1 - 2020/12
N2 - Aerodynamic damping is the key parameter to determine the stability of vibrating blade rows in turbomachinery design. Both, the assessments of flutter and forced response vibrations need an accurate estimate of the aerodynamic damping to reduce the risk of high cycle fatigue that may result in blade loss. However, only very few attempts have been made to measure the aerodynamic damping of rotating blade rows experimentally under realistic operating conditions, but always with friction damping being present. This study closes the gap by providing an experiment in which a turbine blisk is used to eliminate friction damping at the blade roots and thereby isolate aerodynamic damping. The blades are excited acoustically and the resulting nodal diameter modes are measured using an optical tip-Timing system in order to realize a fully non-intrusive setup. The measured vibration data are fitted to a single degree-of-freedom model (SDOF) to determine the aerodynamic damping. The results are in good accordance with the time-linearized CFD simulation. It is observed, however, that not only the sweep rate of the acoustic excitation but also the variation of the rotational frequency during the sweep excitation, and the excitation frequency influence the apparent damping.
AB - Aerodynamic damping is the key parameter to determine the stability of vibrating blade rows in turbomachinery design. Both, the assessments of flutter and forced response vibrations need an accurate estimate of the aerodynamic damping to reduce the risk of high cycle fatigue that may result in blade loss. However, only very few attempts have been made to measure the aerodynamic damping of rotating blade rows experimentally under realistic operating conditions, but always with friction damping being present. This study closes the gap by providing an experiment in which a turbine blisk is used to eliminate friction damping at the blade roots and thereby isolate aerodynamic damping. The blades are excited acoustically and the resulting nodal diameter modes are measured using an optical tip-Timing system in order to realize a fully non-intrusive setup. The measured vibration data are fitted to a single degree-of-freedom model (SDOF) to determine the aerodynamic damping. The results are in good accordance with the time-linearized CFD simulation. It is observed, however, that not only the sweep rate of the acoustic excitation but also the variation of the rotational frequency during the sweep excitation, and the excitation frequency influence the apparent damping.
KW - Aeromechanical instabilities
KW - Measurement techniques
KW - Turbine blade and measurement advancements
UR - http://www.scopus.com/inward/record.url?scp=85101600282&partnerID=8YFLogxK
U2 - 10.1115/1.4048192
DO - 10.1115/1.4048192
M3 - Article
AN - SCOPUS:85101600282
VL - 142
JO - Journal of turbomachinery
JF - Journal of turbomachinery
SN - 0889-504X
IS - 12
M1 - 121011
ER -