TY - CHAP A1 - Figaschewsky, Felix A1 - Giersch, Thomas A1 - Kühhorn, Arnold T1 - Forced Response Prediction of an Axial Turbine Rotor With Regard to Aerodynamically Mistuned Excitation T2 - ASME Turbo Expo 2014: Turbine Technical Conference and Exposition, Volume 7B: Structures and Dynamics, Düsseldorf, Germany, June 16–20, 2014, Paper GT2014-25896 N2 - The design of both efficient and reliable turbomachinery blades demands a detailed knowledge of static and dynamic forces during operation. This paper aims to contribute to the proper identification of dynamic excitation mechanisms acting on an axial turbine rotor, particularly with regard to deviations of the NGV’s nominal geometry due to the use of variable vanes or tolerances in manufacturing. As variations of the NGV’s geometry disturb the perfectly periodic pattern of the downstream flow features, other spectral components than those correlated with the number of stator vanes are possible to appear. These frequency components may lead to low engine order excitation of fundamental blade modes at high engine speeds. Under these operating conditions the rotor is already highly loaded with centrifugal forces and additional dynamic excitation may cause unacceptable stresses. Thus aerodynamic mistuning might be a limiting criterion for the design of a highly loaded turbine rotor. Within this paper 2 dimensional CFD-models are used to investigate both, the determination of the wake of a geometric mistuned stator guide vane and the influence of the resulting excitation on the adjacent rotor stage due to aerodynamically mistuned flow. In order to generate a mistuned NGV geometry, variations of pitch and stagger angle are taken into account and a mesh morpher is used to produce computational domains of the mistuned geometry on the basis of a nominal mesh. Additionally a simplified reconstruction process based on a set of CFD computations will be introduced, being able to reproduce the spectral components of the mistuned wake by specifying a certain geometric mistuning distribution. The prediction of the resulting modal forces is carried out in time domain and approaches with lower fidelity are investigated with respect to their capability of reproducing the key features of an aerodynamically mistuned excitation mechanism. KW - Rotors KW - Turbines Y1 - 2014 SN - 978-0-7918-4577-6 U6 - https://doi.org/10.1115/GT2014-25896 PB - ASME ER - TY - CHAP A1 - Rauer, Georg A1 - Kühhorn, Arnold A1 - Springmann, Marcel T1 - Residual Stress Modelling and Inverse Heat Transfer Coefficients Estimation of a Nickel-Based Superalloy Disc Forging T2 - ASME Turbo Expo 2014: Turbine Technical Conference and Exposition, Volume 6, Düsseldorf, Germany, June 16–20, 2014, Paper GT2014-25827 N2 - Aero engine disc forgings are subjected to heat treatment operations, i.e., solution treatment followed by quenching and artificial aging, with the aim of achieving improved mechanical material properties. During heat treatment high inhomogeneous temperature gradients and long loading times at elevated temperatures occur and lead to the development and partial relaxation of bulk residual stresses. The intention of this paper is to describe the residual stress modelling of a nickel-based ATI 718Plus® superalloy disc forging. For this purpose, an uncoupled thermomechanical finite element problem is solved consisting of a thermal model based on transient, spatially varying heat transfer coefficients (HTCs) and a stress model incorporating the nonlinear material behaviour to account for thermal induced inelastic deformations. A graphical user interface based application has been created for the automatic estimation of the a priori unknown HTCs by using a serial solution procedure for the two dimensional inverse heat conduction problem (IHCP) based on the function specification method. The estimated temperature fields have been compared at the thermocouple positions with the corresponding measurement data and confirm the suitability of the inverse algorithm to this problem. A rate-independent elasto-plastic constitutive model is used to simulate the residual stress formation while quenching the disc forging. Two creep models have been adjusted to uniaxial tensile test data and applied to simulate the stress relaxation during aging. Finally, this paper presents the numerical results of the stress analysis. Copyright © 2014 by Rolls-Royce Deutschland Ltd & Co KG KW - Nickel KW - Superalloys KW - Forging KW - Stress KW - Modeling Y1 - 2014 SN - 978-0-7918-4575-2 U6 - https://doi.org/10.1115/GT2014-25827 PB - ASME 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 - Giersch, Thomas A1 - Figaschewsky, Felix A1 - Hönisch, Peter A1 - Kühhorn, Arnold A1 - Schrape, Sven T1 - Numerical Analysis and Validation of the Rotor Blade Vibration Response Induced by High Pressure Compressor Deep Surge T2 - ASME Turbo Expo 2014: Turbine Technical Conference and Exposition, Volume 7B: Structures and Dynamics Düsseldorf, Germany, June 16–20, 2014, Paper GT2014-26295 N2 - The following paper presents a numerical analysis of a deep surge cycle of a 4.5 stage research compressor. The resulting unsteady loads are used to determine the response of two particular rotor blade rows that are then compared to strain gauge data from measurements. Within a deep surge cycle the compressor experiences a rapid change of the flow field from forward to reversed flow. This rapid breakdown is linked to a new mean blade load. Hence, the rapid change in blade loads are able to excite fundamental blade modes similar to an impulse load. The resulting vibration magnitudes might reach critical levels. This paper demonstrates two different approaches to evaluate the unsteady flow during a surge cycle. The first uses a three dimensional, time accurate finite volume solver for viscid compressible flows to calculate the transient surge cycle of the compressor. The compressor itself is represented by a multi-blade-row sector model. The second approach makes use of the same solver and compressor domain to determine steady state characteristics of the HPC in forward, stalled and reversed flow. Based on these characteristics an one dimensional finite volume solver for inviscid compressible flows was developed to determine the transient compressor behavior. The one dimensional solver represents the compressor by source terms that are linked to the previously determined steady state characteristics. Copyright © 2014 by Rolls-Royce Deutschland Ltd & Co KG KW - Compressors KW - High pressure (Physics) KW - Numerical analysis Y1 - 2014 SN - 978-0-7918-4577-6 U6 - https://doi.org/10.1115/GT2014-26295 PB - ASME CY - New York, NY ER - TY - CHAP A1 - Rey Villazón, José Maria A1 - Wildow, Toni A1 - Kühhorn, Arnold A1 - Benton, Robert A1 - Göhler, Moritz T1 - Impact of the Secondary Air System Design Parameters on the Calculation of Turbine Discs Windage T2 - ASME Turbo Expo 2014: Turbine Technical Conference and Exposition, Volume 5C: Heat Transfer, Düsseldorf, Germany, June 16–20, 2014, Paper GT2014-26050 N2 - The rotating components in gas turbines are very highly stressed as a result of the centrifugal and thermal loads. One of the main functions of the secondary air system (SAS) is to ensure that the rotating components are surrounded by air that optimizes disc lifing and integrity. The SAS is also responsible for the blade cooling flow supply, preventing hot gas ingestion from the main annulus into the rotor-stator cavities, and for balancing the net axial load in the thrust bearings. Thus, the SAS design requires a multidisciplinary compromise to provide the above functions, while minimizing the penalty of the secondary flows on engine performance. The phenomenon known as rotor-stator drag or windage is defined as the power of the rotor moment acting on its environment. The power loss due to windage has a direct impact on the performance of the turbine and the overall efficiency of the engine. This paper describes a novel preliminary design approach to calculate the windage of the rotor-stator cavities in the front of a typical aero engine HP turbine. The new method is applied to investigate the impact of the SAS design parameters on the windage losses and on the properties of the cooling flows leading to the main annulus. Initially, a theoretical approach is followed to calculate the power losses of each part of the HPT front air feed system. Then, a 1D-network integral model of the cavities and flow passages of the HPT front is built and enhanced with detailed flow field correlations. The new 1D-flow network model offers higher fidelity regarding local effects. A result comparison between the theoretical calculation and the prediction of the enhanced flow network model puts forward the relevance of the local flow field effects in the design concept of the SAS. Using the enhanced 1D-flow network models, the SAS design parameters are varied to assess their influence on the windage and pumping power calculation. As a conclusion, the paper shows how the SAS design can have a significant influence on the HPT overall power and the air that is fed back into the turbine blade rows. Controlling these features is essential to bid a competitive technology in the aero engine industry. Copyright © 2014 by Rolls-Royce Deutschland Ltd & Co KG KW - Design KW - Turbines KW - Disks Y1 - 2014 SN - 978-0-7918-4573-8 U6 - https://doi.org/10.1115/GT2014-26050 PB - ASME CY - New York, NY ER - TY - CHAP A1 - Beirow, Bernd A1 - Maywald, Thomas A1 - Kühhorn, Arnold T1 - Mistuning and Damping Analysis of a Radial Turbine Blisk in Varying Ambient Conditions T2 - ASME Turbo Expo 2014: Turbine Technical Conference and Exposition, Volume 7B: Structures and Dynamics Düsseldorf, Germany, June 16–20, 2014, Paper GT2014-25521 N2 - A mistuned radial turbine impeller is analyzed with respect to the impact of varying ambient pressures and temperatures as well on frequency response functions and modal damping ratios. Beginning at room conditions, a finite element model of an impeller wheel at rest is updated based on experimentally determined mistuning in terms of blade dominated frequencies. The following numerical forced response analyses yield a maximum blade displacement amplification of 67% compared to the tuned reference. In addition, modal damping ratios are determined in dependence on the ambient pressure ranging from technical vacuum at 1 mbar up to 6000 mbar in a pressure chamber. Shaker excitation and laser Doppler vibrometry response measurement is employed in this context. A linear dependence of modal damping ratios on ambient pressure and a dominating damping contribution of the surrounding air even for higher modes could be proved. Moreover, the experimental determination of frequency response functions (FRF) at technical vacuum yields a better separation of resonance peaks compared to room conditions at 1013 mbar and hence, this data allows for more accurate model-updates in principle. It is proved that numerical models updated regarding mistuning at room conditions are well suited to predict the forced response at arbitrary pressures if measured modal damping ratios at these pressures are considered. Finally, within analyzing the effect of increasing structural temperatures with the surrounding air at 1013 mbar included slightly decreasing resonance frequencies but strongly increasing FRF-amplitudes are determined. Copyright © 2014 by ASME KW - Damping KW - Turbines Y1 - 2014 SN - 978-0-7918-4577-6 U6 - https://doi.org/10.1115/GT2014-25521 PB - ASME ER - TY - CHAP A1 - Behnam, Nouri A1 - Kühhorn, Arnold T1 - Automated CAE process for thermo-mechanical lifing prediction of a parameterized turbine blade with internal cooling T2 - Joined 11th World Congress on Computational Mechanics (WCCM XI), 5th European Conference on Computational Mechanics (ECCM V), 6th European Conference on Computational Fluid Dynamics (ECFD VI) conference Y1 - 2014 UR - http://www.wccm-eccm-ecfd2014.org/admin/files/fileabstract/a2070.pdf ER - TY - CHAP A1 - Rey Villazón, José Maria A1 - Kühhorn, Arnold T1 - Adaptive CFD-Enhanced Windage Modelling for Aero Engine Turbine Rotor-Stator Cavities T2 - Joined 11th World Congress on Computational Mechanics (WCCM XI), 5th European Conference on Computational Mechanics (ECCM V), 6th European Conference on Computational Fluid Dynamics (ECFD VI) conference Y1 - 2014 UR - http://www.wccm-eccm-ecfd2014.org/admin/files/fileabstract/a1666.pdf ER - TY - CHAP A1 - Behnam, Nouri A1 - Kühhorn, Arnold T1 - Interdisciplinary Analysis of a Turbine Blade With Internal Cooling Including Local Distribution and Rotation Effects T2 - 11th AIAA/ASME Joint Thermophysics and Heat Transfer Conference, Atlanta, GA KW - gas turbine engines KW - cooling Y1 - 2014 UR - http://arc.aiaa.org/doi/abs/10.2514/6.2014-2388 SN - 978-1-62410-281-3 PB - AIAA CY - Reston, VA ER - TY - CHAP A1 - Beirow, Bernd A1 - Kühhorn, Arnold A1 - Golze, Mark A1 - Klauke, Thomas T1 - Experimentelle Untersuchungen des strukturdynamischen Verhaltens von Hochdruckverdichterschaufeln in Integralbauweise (Blisks) mittels Laser-Doppler-Vibrometrie KW - Blisks KW - Integralbauweise Y1 - 2004 ER - TY - CHAP A1 - Rey Villazón, José Maria A1 - Berthold, Martin A1 - Kühhorn, Arnold T1 - Adaptive Flow Field Thermal Modeling Techniques for Turbine Rotor-Stator Cavities T2 - Proceedings of ASME Turbo Expo 2013, San Antonio, Texas, USA , June 3-7, 2013, Vol. 3C: Heat Transfer, Paper GT2013-94845 Y1 - 2013 UR - http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=1776262 SN - 978-0-7918-5516-4 U6 - https://doi.org/10.1115/GT2013-94845 PB - ASME CY - New York ER - TY - THES A1 - Klauke, Thomas T1 - Schaufelschwingungen integraler, realer Verdichterräder im Hinblick auf Verstimmung und Lokalisierung KW - Schaufelschwingung KW - Verdichter KW - Flattern Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:co1-opus-4081 ER - TY - CHAP A1 - Springmann, Marcel A1 - Scherzer, M. A1 - Kuna, M. A1 - Kühhorn, Arnold T1 - Numerical simulation of localization phenomena in the frame of damage parameter identification T2 - Seminar: Materials modeling, FE simulations of the behavior of modern industrial materials including failure, 5th - 6th December 2006, Niedernhausen (Wiesbaden), Germany Y1 - 2006 SN - 1-874376-19-0 PB - NAFEMS Contact Nordic Countries CY - Grafing b. München ER - TY - CHAP A1 - Keskin, Akin A1 - Kober, Markus A1 - Stelldinger, Enrico A1 - Kühhorn, Arnold A1 - Böhm, Holger A1 - Hornig, Andreas A1 - Hufenbach, Werner T1 - On the quantification of errors of a pre-processing effort reducing contact meshing approach : AIAA 2015-0408 T2 - 53rd AIAA Aerospace Sciences Meeting 2015, Kissimmee, Florida, USA, 5 - 9 January 2015, held at the AIAA SciTech Forum 2015, vol. 4 Y1 - 2015 SN - 978-1-5108-0117-2 U6 - https://doi.org/10.2514/6.2015-0408 SP - 3113 EP - 3124 PB - Curran CY - Red Hook, NY ER - TY - CHAP A1 - Rey Villazón, José Maria A1 - Wildow, Toni A1 - Kühhorn, Arnold A1 - Benton, Robert A1 - Eydam, Tobias T1 - Advanced Turbine Preliminary Design Environment for the automatic Generation of Secondary Air System Models T2 - ASME Turbo Expo 2015: Turbine Technical Conference and Exposition Volume 7A: Structures and Dynamics Montreal, Quebec, Canada, June 15–19, 2015 N2 - The design and development process of an aero engine is a complex and time-consuming task that involves many disciplines and company departments with different objectives and requirements. Along the preliminary design phase, multiple concepts are assessed in order to select a competitive technology. The engine design process, which was traditionally subdivided into modular component tasks, is nowadays considered as a multi-disciplinary workflow. Having recognized the need for developing advanced turbine preliminary design tools, this work focuses on enhancing the integration of turbine design disciplines, improving the accuracy of models and speeding the time to generate models. The proposed process facilitates an automated turbine Secondary Air System (SAS) and turbine discs concept definition. Furthermore, the process of CAD models and flow network models generation is accelerated via automation of the engineering workflow. This is accomplished through a novel Java based data model, where the design of turbine discs and SAS features is captured in a programmable framework. In the application section, the preliminary design definition of a reference HP turbine subsystem is replicated using the newly developed common design environment. The automated workflow is then used to generate the corresponding CAD models, recognize the subsystem flow network, and generate the 1D flow network model. The results are then compared to the experimentally validated model of a reference engine. As conclusion, the automated workflow offers a quick and parametric model generation process, while providing a good level of fidelity for the preliminary design phase. Copyright © 2015 by Rolls-Royce Deutschland Ltd & Co KG KW - Design KW - Turbines Y1 - 2015 SN - 978-0-7918-5676-5 U6 - https://doi.org/10.1115/GT2015-42661 PB - ASME CY - New York, NY ER - TY - CHAP A1 - Wagner, Frank A1 - Kühhorn, Arnold T1 - Response surface based robust design optimization on the example of a high pressure turbine blade T2 - 8. Dresdner Probabilistik-Workshop, Technische Universität Dresden, 08.-09. Okt. 2015 N2 - Nowadays in a product design process the manufacturing tolerances have to be considered. Therefore a deterministic optimization needs to be converted into a robust design optimization. Usually the reference geometry is represented by a parametric model and an appropriate set of default parameters. In the robust design approach this set is replaced by a set of distributed parameters. These distributions are known from a previous design or needs to be estimated. This work is about a robust design and multi objective optimization of a high pressure turbine blade (first row) from an actual aero engine. The multidisciplinary objectives are the combined life of the aero-foil (LCF and creep) for the outer and inner geometry, the efficiency and the mass of the blade. For the input set different kinds of parameter will be examined. Apart from the major geometry parameters, which represent the external surface of the blade, parameters for material and boundary conditions will be investigated as well. The used workflow contains the Rolls-Royce tool parablading for the creation of the external aero-foil, Siemens NX for general geometry manipulation, Hydra as Navier-Stokes solver and SC03 for the structural problem and is set up in the automation software ISight. Focus of this work is the creation of response surfaces and physical integrity of the delivered results. Therefore, different validation criteria will be consulted. These are implemented in a Matlab toolbox and tested on typical optimization test problems. Based on the validated response surfaces a huge number of evaluations is possible, which is necessary for a robust design optimization. As the major result a set of Pareto optimal designs will be delivered. Y1 - 2015 UR - http://www.probabilistik.de/abstract/abstract_15_wagner.html UR - http://www.probabilistik.de/prog_15.html CY - Dresden ER - TY - CHAP A1 - Giersch, Thomas A1 - Kühhorn, Arnold A1 - Figaschewsky, Felix T1 - Probabilistic Analysis of Low Engine Order Excitation Due to Geometric Perturbations of Upstream Nozzle Guide Vanes : ISABE-2015-20165 T2 - Conference Proceedings from the 22nd International Symposium on Air Breathing Engines, October 25-30, 2015, Phoenix, Arizona Y1 - 2015 UR - http://hdl.handle.net/2374.UC/745749 SP - 1 EP - 9 PB - ISABE ER - TY - CHAP A1 - Maywald, Thomas A1 - Beirow, Bernd A1 - Heinrich, Christoph Rocky A1 - Kühhorn, Arnold T1 - Vacuum Spin Test Series of a Turbine Impeller with Focus on Mistuning and Damping by Comparing Tip Timing and Strain Gauge Results T2 - ASME Turbo Expo 2015: Turbine Technical Conference and Exposition Volume 7B: Structures and Dynamics Montreal, Quebec, Canada, June 15–19, 2015 N2 - This paper describes preparation, execution and evaluation of a comprehensive bladed disk spin test series. At the example of an turbine impeller the effects of rotation and temperature are analyzed with special focus on mistuning and damping. The forced response is measured synchronously via 13 identical positioned strain gauges on each blade as well as via blade tip-timing. Subsequently it is possible to compare the results of both systems. During the test series rotational speed varies in the range from 10.000 up to 19.000 RPM. Simultaneously, the wheel is heated up to 820 K by an oven. A number of pre-selected natural frequencies, damping ratios and operating deflection shapes are evaluated and compared with respect to different rotational speeds and impeller temperatures. Copyright © 2015 by ASME KW - Rotation KW - Vacuum KW - Impellers KW - Damping KW - Turbines KW - Strain gages Y1 - 2015 SN - 978-0-7918-5677-2 U6 - https://doi.org/10.1115/GT2015-42649 PB - ASME CY - New York, NY ER - TY - CHAP A1 - Wagner, Frank A1 - Kühhorn, Arnold A1 - Parchem, Roland T1 - Robust design optimization applied to a high pressure turbine blade based on surrogate modelling techniques T2 - ASME Turbo Expo 2015: Turbine Technical Conference and Exposition Volume 7A: Structures and Dynamics Montreal, Quebec, Canada, June 15–19, 2015 N2 - To achieve reverse objectives in engine design, advanced modelling and analysis methods are among the key research technologies. In the presented work, a robust design optimization of a first stage high pressure turbine blade has been carried out. This blade derives from a current production of a Rolls-Royce aero engine. The motivation of this work is to show that the methodology of robust design optimization can be applied to high pressure turbine blades. A fully automated workflow, which encapsulated the integral blade design and analysis process, has been used. The main workflow objective is a representative life value of the external surface of the blade. In addition, the workflow enables the engineering uses to consider sub objectives like mass, efficiency and life at critical locations of the blade. These can also be taken into account in the multi-objective robust design optimization. This research also focuses on the use of surrogate models, with attention to the delivery of a physically correct result. For this purpose, the validation of the applied methods has a huge significance and a toolbox was created to generate and evaluate the quality of the surrogate models. In the present case sixteen geometry parameters were considered. In order to show that this methodology is not limited to geometry variation, parameters for material specification and for boundary conditions were varied in addition. The surrogate model was trained by the workflow generated DoE-data and could be used for different kinds of optimization. As a conclusion, it has been demonstrated that the methodology can be used for the engineering design process of turbine blades, while delivering physically correct results. The different techniques for surrogate modelling were examined and compared. With the help of these surrogate models, an optimization of life, mass and efficiency with 22.5 million evaluations was possible. Finally, an overview of the methodology for the case of a real world turbine blade could be given, and an improved blade in the sense of multi-objective robust design was found. Copyright © 2015 by Rolls-Royce Deutschland Ltd & Co KG KW - Turbine blades KW - High pressure (Physics) KW - Design KW - Modeling KW - Optimization Y1 - 2015 SN - 978-0-7918-5676-5 U6 - https://doi.org/10.1115/GT2015-42365 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 - CHAP A1 - Figaschewsky, Felix A1 - Kühhorn, Arnold T1 - Analysis of Mistuned Blade Vibrations Based on Normally Distributed Blade Individual Natural Frequencies T2 - ASME Turbo Expo 2015: Turbine Technical Conference and Exposition Volume 7B: Structures and Dynamics Montreal, Quebec, Canada, June 15–19, 2015 N2 - With increasing demands for reliability of modern turbomachinery blades the quantification of uncertainty and its impact on the designed product has become an important part of the development process. This paper aims to contribute to an improved approximation of expected vibration amplitudes of a mistuned rotor assembly under certain assumptions on the probability distribution of the blade’s natural frequencies. A previously widely used lumped mass model is employed to represent the vibrational behavior of a cyclic symmetric structure. Aerodynamic coupling of the blades is considered based on the concept of influence coefficients leading to individual damping of the traveling wave modes. The natural frequencies of individual rotor blades are assumed to be normal distributed and the required variance could be estimated due to experiences with the applied manufacturing process. Under these conditions it is possible to derive the probability distribution of the off-diagonal terms in the mistuned equations of motions, that are responsible for the coupling of different circumferential modes. Knowing these distributions recent limits on the maximum attainable mistuned vibration amplitude are improved. The improvement is achieved due to the fact, that the maximum amplification depends on the mistuning strength. This improved limit can be used in the development process, as it could partly replace probabilistic studies with surrogate models of reduced order. The obtained results are verified with numerical simulations of the underlying structural model with random mistuning patterns based on a normal distribution of individual blade frequencies. Copyright © 2015 by ASME KW - Vibration KW - Blades Y1 - 2015 SN - 978-0-7918-5677-2 U6 - https://doi.org/10.1115/GT2015-43121 PB - ASME CY - New York, NY ER - TY - THES A1 - Beirow, Bernd T1 - Experimentelle und theoretische Untersuchungen des dynamischen Verhaltens von Fernmeldetürmen Y1 - 2000 PB - BTU, Lehrstuhl Statik und Dynamik CY - Cottbus ER - TY - CHAP A1 - Nouri, Behnam A1 - Lehmann, Knut A1 - Kühhorn, Arnold T1 - Investigations on Nusselt Number Enhancement in Ribbed Rectangular Turbine Blade Cooling Channels of Different Aspect Ratios and Rotation Numbers T2 - ASME Turbo Expo 2013: Turbine Technical Conference and Exposition, San Antonio, Texas, USA, June 3–7, 2013, Vol. 3A, Heat Transfer, Paper GT2013-94710 N2 - In the drive for higher cycle efficiencies in gas turbine engines, turbine blades are seeing an increasingly high heat load. This in turn demands improvements in the internal cooling system and a better understanding of both the level and distribution of the internal heat-transfer. A typical approach to enhance the internal cooling of the turbine blade is by casting angled ‘low blockage’ ribs on the walls of the cooling channels. The objective of the present paper is to determine the detailed Nusselt number distribution in rectangular internal channels with ribs. This knowledge can be used to guide the overall design e.g. to achieve high levels of heat-transfer where required. The effects of rotation as well as the interaction effects of the position and direction of ribs on opposite walls of the cooling channel have been investigated. Numerical calculations have been carried out using the commercial CFD code Fluent to investigate the local Nusselt number enhancement factor in rectangular ducts of different aspect ratios (0.5, 1 and 2) which have 45° or 90° angled ribs located on two opposite walls. This has been studied for different Rotation number Ro (0–0.45) and with a Reynolds number >30000. The first series of studies has been carried out with the same experimental setup as by Han [1]. The geometry was slightly changed to avoid the effect of high heat transfer at the entry. This study identifies important vortical structures, which are dependent on the direction and the position of the ribs. This has a profound effect on the distribution of heat-transfer within the passage. It is shown that the two smooth walls of the duct have different average Nusselt number ratio Nu/NuFD enhancement depending on the rib angle. In addition, based on numerical investigations, simple correlations have been developed for the rotational influence of the internal Nusselt number distribution. A major finding is that the effect of rotation is dominant for low aspect ratio channels and the local enhancement due to the rib position and angle is more dominant for high aspect ratio channels. Y1 - 2013 UR - http://proceedings.asmedigitalcollection.asme.org/proceeding.aspx?articleid=1776088 SN - 978-0-7918-5514-0 U6 - https://doi.org/10.1115/GT2013-94710 PB - ASME CY - New York 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 - JOUR A1 - Kühhorn, Arnold A1 - Beirow, Bernd A1 - Golze, Mark A1 - Studener, Johannes T1 - Strukturmechanische Analyse einer Triebwerksverdichter-Schaufelscheibe N2 - Die Verbesserung von Kalibriermethoden für Hochdruckverdichterstufen in ausgeführter Integralbauweise verlangt von den Ingenieuren ein detaillierteres Verständnis der strukturdynamischen Zusammenhänge dieses komplexen Bauteils. Als Ausgangsbasis werden zunächst für das perfekte Normdesign bei Ausnutzung der vorliegenden zyklischen Rotationssymmetrie numerische Ergebnisse vorgestellt. Dabei stehen bezüglich des Schwingverhaltens die Kopplungseffekte zwischen Scheibe und Schaufeln im Mittelpunkt, wobei experimentelle Untersu-chungen am realen Bauteil ergänzend hinzugezogen werden. Zukünftig wird in einem weiteren Schritt im Rahmen erheblich aufwendigerer Berechnungen mit der Berücksichtigung von Imperfektionen hinsichtlich der filigranen Schaufeln die Rotationssymmetrie aufgegeben und somit die Basis für eine gezielte Beeinflussung des Schwingverhaltens infolge von Mistuning - Effekten geschaffen. KW - FEM-Simulation KW - Experimentelle Modalanalysen KW - Kopplungseffekte Y1 - 2002 ER - TY - CHAP A1 - Beirow, Bernd A1 - Kühhorn, Arnold A1 - Golze, Mark A1 - Parchem, Roland A1 - Johann, E. T1 - Experimentelle und numerische Untersuchungen hinsichtlich einer Festigkeitsauslegungsoptimierung von Hochdruck-Verdichter-Schaufelscheiben unter besonderer Berücksichtigung von Mistuningeffekten T2 - Deutscher Luft- und Raumfahrtkongress 2003, München, 17. bis 20. November 2003, Bd. 2 KW - Festigkeitsauslegungsoptimierung KW - Hochdruck-Verdichter-Schaufelscheiben KW - Mistuningeffekte Y1 - 2003 SP - 1495 EP - 1504 PB - DGLR CY - Bonn ER - TY - CHAP A1 - Klauke, Thomas A1 - Kühhorn, Arnold A1 - Golze, Mark A1 - Villwock, J. A1 - Lenk, Olaf T1 - Finite-Elemente-Anwendung neuerer Faserverbund-Bruchkriterien und deren Verifizierung mittels CFK-Bauteilprüfung T2 - Deutscher Luft- und Raumfahrtkongress 2003, München, 17. bis 20. November 2003, Bd. 1 KW - FEM KW - Faserverbund KW - CFK-Bauteilprüfung Y1 - 2003 SP - 113 EP - 120 PB - Dt. Ges. für Luft- und Raumfahrt CY - Bonn ER - TY - CHAP A1 - Studener, Johannes A1 - Kühhorn, Arnold T1 - FE-Simulation des thermischen Aufheizvorganges eines Silizium-Wafers im RTA (Rapid Thermal Anneal) - Prozess T2 - Tagungsband, 15. Deutschsprachige ABAQUS-Benutzerkonferenz, 22. - 23. September 2003, Fulda KW - Silizium-Wafer KW - RTA-Prozess KW - Simulation Y1 - 2003 PB - ABAQUS Deutschland GmbH CY - Aachen [u.a.] ER - TY - CHAP A1 - Kober, Markus A1 - Kühhorn, Arnold A1 - Stelldinger, Enrico A1 - Keskin, Akin T1 - Considerations About the Necessary Mesh Density of Bearings in Detailed Finite Element Models T2 - ASME Turbo Expo 2014: Turbine Technical Conference and Exposition, Volume 7B: Structures and Dynamics Düsseldorf, Germany, June 16–20, 2014, Paper GT2014-25624 N2 - In order to predict properly the behavior of very complex mechanical models, much focus needs to be done on the level of model details as well as the techniques used to predict component movements based on mechanical and thermal loads. In particular bearings and joints play a significant role in big model assemblies such as aero-engines where most of the structures are modeled by solid elements rather than using traditional shell or beam elements. This approach is very complex and expensive in terms of computational effort however can lead to increased simulation accuracy when done properly. This publication will answer questions related to the modeling techniques required for detailed bearings (not only rotor bearings) and joints of an aero-engine application where these components are not idealized or simplified, i.e. the ball in a ball joint is meshed by solid elements. The investigation will discuss the question about the number of elements needed to mesh a ball joint in such a way that a correct rotation is possible. If the mesh is too coarse, a rotation would be impossible due to the faceting of the rotating parts. It will be shown that a proper rotation depends on a correct relation between the radius of the inner ball, the gap size of the bearing and the number of nodes in the circumferential direction. For this relation an analytical formula has been derived and successfully tested at some examples. Furthermore, some finite element codes offer the possibility of smoothed contact surfaces. These options improve the situation but they might cause issues too. For this reason these smoothed contact options are also considered under the aspects mentioned above. Copyright © 2014 by Rolls-Royce Deutschland Ltd & Co KG KW - Density KW - Bearings Y1 - 2014 SN - 978-0-7918-4577-6 U6 - https://doi.org/10.1115/GT2014-25624 PB - ASME ER - TY - GEN A1 - Klauke, Thomas A1 - Kühhorn, Arnold A1 - Beirow, Bernd A1 - Golze, Mark T1 - Numerical Investigations of Localized Vibrations of Mistuned Blade Integrated Disks (Blisks) Y1 - 2009 ER - TY - CHAP A1 - Stelldinger, Enrico A1 - Kühhorn, Arnold A1 - Kober, Markus T1 - Otimization of a Carbon-fiber-reinforced Plastic Composite Structure using the Example of a Wing Rigger KW - Optimization KW - Composite KW - Wing Rigger Y1 - 2011 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 - 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 - 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 - Höhnisch, Peter A1 - Kühhorn, Arnold A1 - Beirow, Bernd T1 - Experimental and Numerical Analysis of Radial Turbine Bliks with Regard to Mistuning KW - Tadial KW - Turbine KW - Vibration KW - Mistuning KW - Model Update Y1 - 2011 ER - TY - THES A1 - Beirow, Bernd T1 - Grundlegende Untersuchungen zum Schwingungsverhalten von Verdichterlaufrädern in Integralbauweise Y1 - 2009 SN - 978-3-8322-8729-0 PB - Shaker CY - Aachen ER - TY - CHAP A1 - Kühhorn, Arnold A1 - Beirow, Bernd A1 - Strehlau, Ulrik T1 - Zum Schwingungsverhalten integraler Hochdruckverdichterlaufräder Y1 - 2009 ER - TY - JOUR A1 - Grosch, A. A1 - Beirow, Bernd T1 - Ausgewählte bauphysikalische Probleme von Wohngebäuden in Stahl-Leichtbauweise Y1 - 2001 ER - TY - CHAP A1 - Springmann, Marcel A1 - Kühhorn, Arnold A1 - Rauer, Georg A1 - Giersch, Thomas T1 - Constitutive Modelling of Plastic and Creep Behavior of the Nickel Base Superalloy ALLVAC® 718PLUS® under Heat Treatment Conditions KW - Behavior KW - Nickel-Based Superalloy KW - Heat Treatment Conditions Y1 - 2011 ER - TY - CHAP A1 - Maywald, Thomas T1 - Grundlegende Charakterisierung des Eigenschwingverhaltens eines zyklisch symmetrischen Mehrmassenschwingers mittels analytischer Methoden T2 - Deutscher Luft- und Raumfahrtkongress, Tagungsband Bremen 2011, Manuskripte KW - Eigenschwingverhalten KW - Mistuning KW - zyklisch symmetrischer Mehrmassenschwinger Y1 - 2011 SP - 809 EP - 816 PB - DGLR CY - Bonn ER - TY - CHAP A1 - Hönisch, Peter A1 - Kühhorn, Arnold T1 - Mistuning und Dämpfung von Radialturbinen KW - Mistuning KW - Dämpfung KW - Radialturbine Y1 - 2011 ER - TY - CHAP A1 - Kühhorn, Arnold A1 - Beirow, Bernd A1 - Parchem, Roland A1 - Klauke, Thomas T1 - Schaufelschwingungen bei realen Verdichter-Integralrädern (BLISK) T2 - Deutscher Luft- und Raumfahrtkongress 2006, Braunschweig, 06. bis 09. November 2006, Bd. 2 KW - Schaufelschwingungen KW - Blisk Y1 - 2006 SP - 1199 EP - 1208 PB - Dt. Ges. für Luft- und Raumfahrt CY - Bonn ER - TY - CHAP A1 - Springmann, Marcel A1 - Filipiak, A. T1 - Automatische Generierung eines vereinfachten Triebwerkmodells KW - Triebwerk Y1 - 2006 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 - 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 - CHAP A1 - Schrape, S. A1 - Kühhorn, Arnold A1 - Golze, Mark T1 - Simulation fluidgedämpfter Strukturschwingungen durch partitionierte Fluid-Struktur-Kopplung mittels MpCCI KW - Fluid-Struktur-Kopplung Y1 - 2006 ER - TY - JOUR A1 - Schrape, S. A1 - Kühhorn, Arnold A1 - Golze, Mark T1 - Simulation fluidgedämpfter Strukturschwingungen mittels partitioniertem Kopplungssatz via MpCCI JF - NAFEMS-Magazin KW - fluidgedämpfte Strukturschwingungen Y1 - 2006 VL - 2 IS - 4 SP - 41 EP - 49 ER - TY - CHAP A1 - Schrape, S. A1 - Kühhorn, Arnold A1 - Golze, Mark T1 - Simulation of fluid damped structural vibrations T2 - Proceedings, 7th MpCCI User Forum, February 21st and 22nd 2006, at Schloss Birlinghoven, Sankt Augustin, Germany KW - fluid structures Y1 - 2006 SP - 112 EP - 121 CY - Sankt Augustin ER - TY - CHAP A1 - Strehlau, Ulrik A1 - Kühhorn, Arnold T1 - Experimental and numerical investigations of HPC blisks with a focus on travelling waves T2 - Proceedings of the ASME Turbo Expo 2010, presented at the 2010 ASME Turbo Expo, June 14 - 18, 2010, Glasgow, UK, Volume 6, part B Y1 - 2010 SN - 978-0-7918-4401-4 N1 - GT2010-22463 SP - 865 EP - 878 PB - ASME CY - New York, NY ER - TY - GEN A1 - Maywald, Thomas A1 - Beirow, Bernd A1 - Kühhorn, Arnold T1 - Mistuning und Dämpfung von Radialturbinenrädern T2 - MTZ - Motortechnische Zeitschrift N2 - Moderne Verbrennungskraftmaschinen müssen ein stetig wachsendes Anforderungsprofil in Bezug auf Wirtschaftlichkeit, Leistung und Umweltfreundlichkeit erfüllen. In diesem Zusammenhang hat die Turboaufladung von Verbrennungsmotoren an Bedeutung gewonnen. Bei Turboladern kleiner und mittlerer Baugröße, deren Turbinen einen Durchmesser zwischen 30 und 250 mm aufweisen, kommen vornehmlich gegossene Laufräder zum Einsatz. Am Institut für Verkehrstechnik der Brandenburgischen Technischen Universität Cottbus-Senftenberg wurde im Rahmen eines FVV-Forschungsvorhabens der Einfluss charakteristischer Betriebsgrößen eines Turboladers auf das strukturdynamische Verhalten solcher Radialturbinenräder untersucht. Y1 - 2015 U6 - https://doi.org/10.1007/s35146-015-0043-7 SN - 2192-8843 VL - 76 IS - 06 SP - 68 EP - 75 ER -