TY - CHAP A1 - Schrape, S. A1 - Kühhorn, Arnold A1 - Nipkau, Jens A1 - Beirow, Bernd T1 - Application of Aeroelastic Methods in Compressor Cascade Configurations Using Partitioned Code Coupling Y1 - 2008 ER - TY - CHAP A1 - Schrape, S. A1 - Kühhorn, Arnold A1 - Nipkau, Jens T1 - Determination of Aerodynamic Damping of Axial-Compressor-Blades Using A Bidirectional Fluid-Structure-Simulation T2 - 1st CEAS European Air and Space Conference 2007, Deutscher Luft- und Raumfahrtkongress 2007, 10 - 13 September 2007, Berlin, Germany, Bd. 1 Y1 - 2007 N1 - CEAS-2007-027 SP - 309 EP - 318 PB - Dt. Ges. für Luft- und Raumfahrt CY - Bonn ER - TY - CHAP A1 - Johann, E. A1 - Mueck, B. A1 - Nipkau, Jens T1 - Experimental and Numerical Flutter investigation of the 1st Stage Rotor in 4-Stage High Speed Compressor T2 - Proceedings of the ASME Turbo Expo 2008, presented at the 2008 ASME Turbo Expo, June 9 - 13, 2008, Berlin, Germany, Vol. 5, part A Y1 - 2008 SN - 978-0-7918-4315-4 N1 - GT2008-50698 SP - 769 EP - 778 PB - ASME CY - New York, NY ER - TY - JOUR A1 - Nipkau, Jens A1 - Schrape, S. A1 - Beirow, Bernd A1 - Kühhorn, Arnold T1 - Bestimmung aeroelastischer Parameter einer Hochdruckverdichter Stufe mit Hilfe Fluid-Struktur gekoppelter Berechnungen Y1 - 2008 ER - TY - CHAP A1 - Nipkau, Jens A1 - Kühhorn, Arnold A1 - Schrape, S. T1 - Determination of Aeroelastic Parameters of a High-Pressure-Compressor Stage using Fluid-Structure Interaction Calculations T2 - Seminar: Simulation of Complex Flows (CFD), applications and trends, 10th - 11th March 2008, Wiesbaden, Germany Y1 - 2008 SN - 978-1-87437-633-0 PB - NAFEMS Contact DACH & Nordic Countries CY - Bernau am Chiemsee ER - TY - CHAP A1 - Nipkau, Jens A1 - Kühhorn, Arnold A1 - Schrape, S. T1 - Application of Fluid-Structure-Coupling for the Determination of Aeroelastic Parameters of a High-Pressure-Compressor-Blisk-Stage Y1 - 2008 ER - TY - CHAP A1 - Schrape, S. A1 - Kühhorn, Arnold A1 - Nipkau, Jens T1 - Determination of Aerodynamic Damping of Axial-Compressor-Blades using Fluid-Structure-Interaction Methods Y1 - 2007 ER - TY - CHAP A1 - Beirow, Bernd A1 - Kühhorn, Arnold A1 - Nipkau, Jens T1 - On the Influence of Strain Gauge Instrumentation on Blade Vibrations of Integral Blisk Compressor Rotors Applying a Discrete Model T2 - Proceedings of the ASME Turbo Expo 2009, presented at the 2009 ASME Turbo Expo, June 8 - 12, 2009, Orlando, Florida, USA Y1 - 2009 SN - 978-0-7918-4887-6 N1 - GT2009-59207 SP - 245 EP - 254 PB - ASME CY - New York, NY ER - TY - THES A1 - Nipkau, Jens T1 - Analysis of mistuned blisk vibrations using a surrogate lumped mass model with aerodynamic influences N2 - The present work presents the aeroelastic analyses of mistuned blisk forced response employing a surrogate lumped mass model with aerodynamic influence coefficients. Prior to these, the state of the art in mistuning analysis is summarised and the theoretical background of the structural as well as the aerodynamical model employed in this work is illustrated. Consequently, the validation of the aeroelastic methods is presented at the example of the compressor likeStandard Configuration 10, a standardised test case of an aerofoil vibrating in a cascade, and the aerodynamical model is validated against bidirectionally coupled fluid structure interaction simulations of a 2D compressor rotor model. Finally, the aeroelastic behaviour of a mistuned blisk is analysed featuring measured mistuning patterns and extensive probabilistic analyses of mistuned blisk forced response. Die vorliegende Arbeit beschäftigt sich mit der Analyse erzwungener Schwingungen von verstimmten Verdichterlaufrädern unter Verwendung eines diskreten Ersatzmodells und aerodynamischen Einflusskoeffizienten. Zunächst werden der Stand der Technik bezogen auf die Untersuchung verstimmter Systeme zusammengefasst und die theoretischen Hintergründe des verwendeten Struktur- sowie aerodynamischen Modells dargestellt. Im Anschluss daran werden die aeroelastischen Methoden anhand der Standard Konfiguration 10, einem standardisierten Testfall schwingender Schaufeln in einer Kaskade, überprüft und das aerodynamische Modell mit Hilfe bidirektional gekoppelter Fluid-Struktur-Interaktions-Simulationen eines 2D Modells eines Verdichterrotors validiert. Schließlich wird das aeroelastische Verhalten einer verstimmten Verdichter-Blisk untersucht, wobei neben der Analyse experimentell ermittelter Verstimmungsverteilungen auch ausführliche, probabilistische Simulationen durchgeführt wurden. KW - Mistuned Blisk Vibrations KW - Surrogate Lumped Mass Model Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:co1-opus-22253 SN - 978-3-8440-0302-4 PB - Shaker Verlag CY - Aachen ER - TY - CHAP A1 - Beirow, Bernd A1 - Kühhorn, Arnold A1 - Nipkau, Jens T1 - An Equivalent Blisk Model Considering the Influence of the Air Flow on Blade Vibrations of a Mistuned Compressor Blisk T2 - Vibration Problems ICOVP 2011, The 10th International Conference on Vibration Problems, The 10th International Conference on Vibration Problems KW - Mistuned Compressor Blisk KW - Blade Vibrations KW - Air Flow Y1 - 2011 SN - 978-94-007-2068-8 SP - 549 EP - 555 PB - Springer CY - Berlin [u.a.] ER - TY - CHAP A1 - Beirow, Bernd A1 - Nipkau, Jens A1 - Kühhorn, Arnold T1 - Modal and Aeroelastic Analysis of a Compressor Blisk Considering Mistuning T2 - Proceedings of the ASME Turbo Expo 2011, presented at the ASME 2011 Turbo Expo, June 6 - 10, 2011, Vancouver, British Columbia, Canada, Vol. 6, part B KW - Mistuning KW - Compressor Blisk Y1 - 2011 SN - 978-0-7918-5466-2 N1 - GT2011-45849 SP - 1309 EP - 1319 PB - ASME CY - New York, NY ER - TY - CHAP A1 - Nipkau, Jens A1 - Kühhorn, Arnold A1 - Beirow, Bernd T1 - Modal and Aeroelastic Analysis of a Mistuned Compressor Blisk Using an Equivalent Blisk Model KW - Blisk vibration KW - Mistuning KW - Aerodynamic Influence Coefficients Y1 - 2011 ER - TY - CHAP A1 - Beirow, Bernd A1 - Kühhorn, Arnold A1 - Nipkau, Jens T1 - Schwingungsverhalten integraler Hochdruckverdichterlaufräder unter Berücksichtigung von Fluid-Struktur-Wechselwirkung und Mistuning T2 - 61. Deutscher Luft- und Raumfahrtkongress 2012, 10. - 12. September 2012, Estrel Berlin KW - Mistuning KW - Blisk KW - Aeroelastik Y1 - 2012 UR - http://www.dglr.de/publikationen/2012/281219.pdf N1 - Beitrag DLRK2012-281219 PB - Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth e.V. CY - Bonn ER - TY - CHAP A1 - Beirow, Bernd A1 - Kühhorn, Arnold A1 - Giersch, Thomas A1 - Nipkau, Jens T1 - Forced Response Analysis of a Mistuned Compressor Blisk T2 - ASME Turbo Expo 2013: Turbine Technical Conference and Exposition, San Antonio, Texas, USA, June 3–7, 2013, Vol. 7B, Structures and Dynamics, Paper GT2013-94142 N2 - The forced response of an E3E-type HPC-blisk front rotor is analyzed with regard to varying mistuning and the consideration of the fluid-structure interaction (FSI). For that purpose, a reduced order model is used in which the disk remains unchanged and mechanical properties of the blades namely stiffness and damping are adjusted to measured as well as intentional blade frequency mistuning distributions. The aerodynamic influence coefficient technique is employed to model the aeroelastics. Depending on the blade mode, the exciting engine order and aerodynamic influences it is sought for the worst mistuning distributions with respect to the maximum blade displacement based on optimization analyses. Genetic algorithms using blade alone frequencies as design variables are applied. The validity of the Whitehead-limit is assessed in this context. In particular, the question is addressed if and how far aeroelastic effects, mainly caused by aerodynamic damping, combined with mistuning can even cause a reduction of the forced response compared to the ideally tuned blisk. It is shown that the strong dependence of the aerodynamic damping on the inter-blade phase angle is the main driver for a possible response attenuation considering the fundamental as well as a higher blade mode. Furthermore, the differences to the blisk vibration response without a consideration of the flow and an increase of the disk’s stiffness are discussed. Closing, the influence of pure damping mistuning is analyzed again using optimization. KW - Compressors KW - Blades KW - Blisks KW - Mistuning Y1 - 2013 UR - http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=1776795 SN - 978-0-7918-5527-0 U6 - https://doi.org/10.1115/GT2013-94142 PB - ASME CY - New York ER - TY - GEN A1 - Beirow, Bernd A1 - Giersch, Thomas A1 - Kühhorn, Arnold A1 - Nipkau, Jens T1 - Forced Response Analysis of a Mistuned Compressor Blisk T2 - Journal of Engineering for Gas Turbines and Power N2 - The forced response of an E3E-type high pressure compressor (HPC) blisk front rotor is analyzed with regard to varying mistuning and the consideration of the fluid-structure interaction (FSI). For that purpose, a reduced order model is used in which the disk remains unchanged and mechanical properties of the blades, namely stiffness and damping, are adjusted to measured as well as intentional blade frequency mistuning distributions. The aerodynamic influence coefficient technique is employed to model the aeroelastics. Depending on the blade mode, the exciting engine order, and aerodynamic influences, it is sought for the worst mistuning distributions with respect to the maximum blade displacement based on optimization analyses. Genetic algorithms using blade-alone frequencies as design variables are applied. The validity of the Whitehead limit is assessed in this context. In particular, the question is addressed if and how far aeroelastic effects, mainly caused by aerodynamic damping, combined with mistuning can even cause a reduction of the forced response compared to the ideally tuned blisk. It is shown that the strong dependence of the aerodynamic damping on the interblade phase angle is the main driver for a possible response attenuation considering the fundamental as well as a higher blade mode. Furthermore, the differences to the blisk vibration response without a consideration of the flow and an increase of the disk's stiffness are discussed. Closing, the influence of pure damping mistuning is analyzed again using optimization. KW - Blisk Otimization KW - Mistuning Y1 - 2014 U6 - https://doi.org/10.1115/1.4026537 SN - 1528-8919 VL - 136 IS - 6 ER - TY - GEN A1 - Beirow, Bernd A1 - Giersch, Thomas A1 - Kühhorn, Arnold A1 - Nipkau, Jens T1 - Optimization-Aided Forced Response Analysis of a Mistuned Compressor Blisk T2 - Journal of Engineering for Gas Turbines and Power N2 - The forced response of the first rotor of an engine 3E (technology program) (E3E)-type high pressure compressor (HPC) blisk is analyzed with regard to varying mistuning, varying engine order (EO) excitations and the consideration of aero-elastic effects. For that purpose, subset of nominal system modes (SNM)-based reduced order models are used in which the disk remains unchanged while the Young's modulus of each blade is used to define experimentally adjusted as well as intentional mistuning patterns. The aerodynamic influence coefficient (AIC) technique is employed to model aero-elastic interactions. Furthermore, based on optimization analyses and depending on the exciting EO and aerodynamic influences it is searched for the worst as well as the best mistuning distributions with respect to the maximum blade displacement. Genetic algorithms using blade stiffness variations as vector of design variables and the maximum blade displacement as objective function are applied. An allowed limit of the blades' Young's modulus standard deviation is formulated as secondary condition. In particular, the question is addressed if and how far the aero-elastic impact, mainly causing aerodynamic damping, combined with mistuning can even yield a reduction of the forced response compared to the ideally tuned blisk. It is shown that the strong dependence of the aerodynamic damping on the interblade phase angle is the main driver for a possible response attenuation considering the fundamental blade mode. The results of the optimization analyses are compared to the forced response due to real, experimentally determined frequency mistuning as well as intentional mistuning. KW - Mistuning KW - Forced Response KW - Compressor Blisk Y1 - 2015 U6 - https://doi.org/10.1115/1.4028095 SN - 1528-8919 VL - 137 IS - 1 SP - 012504-1 EP - 012504-10 ER - TY - CHAP A1 - Beirow, Bernd A1 - Kühhorn, Arnold A1 - Giersch, Thomas A1 - Nipkau, Jens T1 - Optimization-Aided Forced Response Analysis of a Mistuned Compressor Blisk T2 - ASME Turbo Expo 2014, Turbine Technical Conference and Exposition, Volume 7B: Structures and Dynamics, Düsseldorf, Germany, June 16–20, 2014, Paper GT2014-25915 N2 - The forced response of the first rotor of an E3E-type high pressure compressor blisk is analyzed with regard to varying mistuning, varying engine order excitations and the consideration of aeroelastic effects. For that purpose, SNM-based reduced order models are used in which the disk remains unchanged while the Young’s modulus of each blade is used to define experimentally adjusted as well as intentional mistuning patterns. The aerodynamic influence coefficient technique is employed to model aeroelastic interactions. Furthermore, based on optimization analyses and depending on the exciting EO and aerodynamic influences it is searched for the worst as well as the best mistuning distributions with respect to the maximum blade displacement. Genetic algorithms using blade stiffness variations as vector of design variables and the maximum blade displacement as objective function are applied. An allowed limit of the blades’ Young’s modulus standard deviation is formulated as secondary condition. In particular, the question is addressed if and how far the aeroelastic impact, mainly causing aerodynamic damping, combined with mistuning can even yield a reduction of the forced response compared to the ideally tuned blisk. It is shown that the strong dependence of the aerodynamic damping on the inter-blade phase angle is the main driver for a possible response attenuation considering the fundamental blade mode. The results of the optimization analyses are compared to the forced response due to real, experimentally determined frequency mistuning as well as intentional mistuning. Copyright © 2014 by Rolls-Royce Deutschland Ltd & Co KG Y1 - 2014 SN - 978-0-7918-4577-6 U6 - https://doi.org/10.1115/GT2014-25915 PB - ASME ER - TY - CHAP A1 - Beirow, Bernd A1 - Kühhorn, Arnold A1 - Figaschewsky, Felix A1 - Nipkau, Jens T1 - Effect of Mistuning and Damping on the Forced Response of a Compressor Blisk Rotor T2 - ASME Turbo Expo 2015: Turbine Technical Conference and Exposition Volume 7A: Structures and Dynamics Montreal, Quebec, Canada, June 15–19, 2015 N2 - The forced response of an E3E-type high pressure compressor blisk front rotor is analyzed with regard to intentional mistuning and its robustness towards additional random mistuning. Both a chosen alternating mistuning pattern and artificial mistuning patterns optimized concerning the forced response are considered. Focusing on three different blade modes, subset of nominal system mode-based reduced order models are employed to compute the forced response. The disk remains unchanged while the Young’s modulus of each blade is used to define the particular mistuning pattern. The well established aerodynamic influence coefficient technique is employed to model aeroelastic coupling and hence to consider the strongly mode- and inter blade phase angle-dependent aerodynamic damping contribution. It has been found that a reduction of the maximum forced response beyond that of the tuned reference can be achieved for particular mistuning patterns and all modes considered. This implies an exciting engine order which would cause a low nodal diameter mode in case of a tuned blisk. At best a nearly 50% reduction of maximum response magnitudes is computed for the fundamental bending mode and large mistuning. The solution proved to be robust towards additional random mistuning of reasonable magnitude, which is of particular interest with regard to a potential technical realization. In case of small mistuning as assumed for the first torsion and the longitudinal bending mode the advantage of achieving response magnitudes beyond the tuned reference gets lost indeed, if random mistuning is superimposed. However, mostly a lower response level is calculated compared to responses obtained from models adjusted to mistuning determined by experiment. Copyright © 2015 by ASME KW - Compressors KW - Damping KW - Rotors Y1 - 2015 SN - 978-0-7918-5677-2 U6 - https://doi.org/10.1115/GT2015-42036 PB - ASME CY - New York, NY ER - TY - GEN A1 - Figaschewsky, Felix A1 - Kühhorn, Arnold A1 - Beirow, Bernd A1 - Giersch, Thomas A1 - Nipkau, Jens A1 - Meinl, Ferdinand T1 - Simplified Estimation of Aerodynamic Damping for Bladed Rotors, Part 2: Experimental Validation During operation T2 - ASME Turbo Expo 2016, Turbomachinery Technical Conference and Exposition, Volume 7B, Structures and Dynamics, Seoul, South Korea, June 13–17, 2016 N2 - Due to increasing requirements of future engine projects, much effort has been spent on the design of more efficient turbomachinery blades in the recent years. Besides aerodynamic efficiency constraints, these designs need to meet structural criteria ensuring that they are safe and robust with respect to High Cycle Fatigue (HCF). The estimation of the resonant vibration amplitude is done based on the aerodynamic force and the overall damping level. Since, for many applications the contribution of mechanical damping is often rather low compared to the aerodynamic counterpart, the determination of the aerodynamic damping is vital for the estimation of the forced vibration response. This second part is meant to contribute to a simplified computation of the aerodynamic damping during operation by making additional assumptions: The investigated mode family shall not suffer from flutter, has a high reduced frequency and the influence of adjacent blades is negligible. Under these circumstances a simplified approach can be introduced that allows for the computation of the mean value of the aerodynamic damping based on a steady state CFD solution of the regarded stage. It is well known, that the aerodynamic damping of a blade mode family depends on the inter blade phase angle (IBPA) and its direction of propagation, which is not covered by the simplified approach. For higher modes the difference between the minimum and maximum damping is often low and the mean value is a good approximation, whereas for fundamental modes there is often a significant difference. However, it is shown that considering a mistuned vibration response of the rotor, the expected value of the mistuned damping exhibits the mean value of IBPA-dependent aerodynamic damping. CFD simulations of an oscillating airfoil indicate a certain validity range of the simplified approach based on a modified reduced frequency and inlet Mach number, which allows to determine for which industrial applications the approach is most suitable. Finally, this range of validity is verified with experimentally determined overall damping values from strain gauge measurements during operation for 2 different industrial applications, an axial compressor stage of a jet engine and a radial turbine stage of a turbocharger. Copyright © 2016 by Rolls-Royce Deutschland Ltd & Co KG Y1 - 2016 SN - 978-0-7918-4984-2 U6 - https://doi.org/10.1115/GT2016-56458 N1 - Paper No. GT2016-56458 PB - ASME CY - New York, NY [u.a.] ER - TY - CHAP A1 - Beirow, Bernd A1 - Kühhorn, Arnold A1 - Nipkau, Jens T1 - Forced Response Reduction of a Compressor Blisk Rotor Employing Intentional Mistuning T2 - Advances in Mechanism Design II, Proceedings of the XII International Conference on the Theory of Machines and Mechanisms, 6.-8.9.2016, Liberec N2 - Using the example of a compressor test blisk with 29 blades different sources of mistuning and their consequences for the forced response are analysed under consideration of aeroelastic effects. In particular the impact of superimposing intentional structural mistuning by both random structural mistuning and aerodynamic mistuning is studied. For this purpose reduced order models of the blisk are adjusted for different mistuning distributions. The mistuning itself is characterized by assigning individual stiffness parameters to each blade. The aeroelastic coupling is included employing aerodynamic influence coefficients. By means of genetic algorithm optimizations, structural mistuning patterns are found which yield a mitigation of the forced response below that of the tuned design reference. Ideally a nearly 50 % reduction of maximum response magnitudes is computed for the fundamental bending mode and large mistuning. The solutions found have been proven to be robust with respect to additional random and aerodynamic mistuning in case of large intentional structural mistuning. Y1 - 2016 SN - 978-3-319-44087-3 U6 - https://doi.org/10.1007/978-3-319-44087-3_29 SP - 223 EP - 229 PB - Springer International Publishing CY - Cham ER -