scholarly journals On Forced Response of a Rotating Integrally Bladed Disk: Predictions and Experiments

2010 ◽  
Author(s):  
Claude Gibert ◽  
Vsevolod Kharyton ◽  
Fabrice Thouverez ◽  
Pierrick Jean
Keyword(s):  
Dynamic Response ◽  
Piezoelectric Actuators ◽  
Travelling Wave ◽  
Forced Response ◽  
Phase Shifting ◽  
Electronic Circuits ◽  
Bladed Disk ◽  
High Pressure Compressor ◽  
Pressure Compressor ◽  
Finite Elements Model

An experimental setup is described which permits to rotate a bladed disk in vacuum and to measure its dynamic response to excitations provided by some embedded piezoelectric actuators. A particular spatial placement of actuators associated with phase-shifting electronic circuits is set for simulating travelling wave excitations with respect to the rotating frame. The system is demonstrated on an actual high-pressure compressor (HCP) integrally bladed disk. The dynamic response of the blisk is analyzed experimentally and results are correlated with those obtained from a simplified finite elements model taking into account Coriolis effect. The paper focuses on the influence of the latter which is most of the time neglected and its implication on the forced response levels is studied into two situations without or with mistuning.

scholarly journals A Numerical Method for the Prediction of Bladed Disk Forced Response

1994 ◽  
Author(s):  
Marc Berthillier ◽  
Marc Dhainaut ◽  
Franck Burgaud ◽  
Vincent Garnier
Keyword(s):  
Numerical Method ◽  
Forced Response ◽  
Cyclic Symmetry ◽  
Element Mesh ◽  
Analytical Methodology ◽  
Bladed Disk ◽  
High Pressure Compressor ◽  
Rotating Structure ◽  
Upstream Flow ◽  
Pressure Compressor

A numerical method has been developed to predict the forced response of bladed disks due to a wake excitation from upstream blade rows. The structure is modelled by a 3D finite element mesh of a bladed disk segment. Using cyclic symmetry, this model provides a modal base for the rotating structure. The aerodynamic damping of the vibratory modes and the excitation pressures on the blades due to the propagation of upstream flow defects are computed separately using the same 3D unsteady Euler analysis software. A modal response solution of the aeromechanical system is then performed. This analytical methodology has been used to study the forced response of an experimental high pressure compressor blisk. The results are analysed and compared with actual rig tests.

scholarly journals Redesign of a High-Pressure Compressor Blade Accounting for Nonlinear Structural Interactions

2014 ◽  
Author(s):  
Alain Batailly ◽  
Mathias Legrand ◽  
Antoine Millecamps ◽  
Sèbastien Cochon ◽  
François Garcin
Keyword(s):  
High Pressure ◽  
Forced Response ◽  
Compressor Blade ◽  
Design Stage ◽  
Blade Design ◽  
Early Integration ◽  
Nonlinear Structural ◽  
High Pressure Compressor ◽  
Structural Interactions ◽  
Pressure Compressor

Recent numerical developments dedicated to the simulation of rotor/stator interaction involving direct structural contacts have been integrated within the Snecma industrial environment. This paper presents the first attempt to benefit from these developments and account for structural blade/casing contacts at the design stage of a high-pressure compressor blade. The blade of interest underwent structural divergence after blade/abradable coating contact occurrences on a rig test. The design improvements were carried out in several steps with significant modifications of the blade stacking law while maintaining aerodynamic performance of the original blade design. After a brief presentation of the proposed design strategy, basic concepts associated with the design variations are recalled. The iterated profiles are then numerically investigated and compared with respect to key structural criteria such as: (1) their mass, (2) the residual stresses stemming from centrifugal stiffening, (3) the vibratory level under aerodynamic forced response and (4) the vibratory levels when unilateral contact occurs. Significant improvements of the final blade design are found: the need for an early integration of nonlinear structural interactions criteria in the design stage of modern aircraft engines components is highlighted.

Numerical Investigations of Localized Vibrations of Mistuned Blade Integrated Disks (Blisks)

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
T. Klauke ◽  
A. Kühhorn ◽  
B. Beirow ◽  
M. Golze
Keyword(s):  
Strain Energy ◽  
Vibration Modes ◽  
Blade Vibration ◽  
Nodal Diameter ◽  
Mode Localization ◽  
Bladed Disk ◽  
High Pressure Compressor ◽  
Localized Vibrations ◽  
Pressure Compressor ◽  
Higher Sensitivity

Blade-to-blade variations of bladed disk assemblies result in local zoning of vibration modes as well as amplitude magnifications, which primarily reduces the high cycle fatigue life of aeroengines. Criteria were introduced to determine the level of these mode localization effects depending on various parameters of a real high pressure compressor blisk rotor. The investigations show that blade vibration modes with lower interblade coupling, e.g., torsion modes or modes with high numbers of nodal diameter lines, have a significantly higher sensitivity to blade mistuning, which can be characterized by the higher percentage of blades on the total blisk strain energy.

scholarly journals Redesign of a High-Pressure Compressor Blade Accounting for Nonlinear Structural Interactions

2014 ◽  
Vol 137 (2) ◽  
Author(s):  
Alain Batailly ◽  
Mathias Legrand ◽  
Antoine Millecamps ◽  
Sébastien Cochon ◽  
François Garcin
Keyword(s):  
High Pressure ◽  
Forced Response ◽  
Compressor Blade ◽  
Design Stage ◽  
Blade Design ◽  
Early Integration ◽  
Nonlinear Structural ◽  
High Pressure Compressor ◽  
Structural Interactions ◽  
Pressure Compressor

Recent numerical developments dedicated to the simulation of rotor/stator interaction involving direct structural contacts have been integrated within the Snecma industrial environment. This paper presents the first attempt to benefit from these developments and account for structural blade/casing contacts at the design stage of a high-pressure compressor blade. The blade of interest underwent structural divergence after blade/abradable coating contact occurrences on a rig test. The design improvements were carried out in several steps with significant modifications of the blade stacking law while maintaining aerodynamic performance of the original blade design. After a brief presentation of the proposed design strategy, basic concepts associated with the design variations are recalled. The iterated profiles are then numerically investigated and compared with respect to key structural criteria such as: (1) their mass, (2) the residual stresses stemming from centrifugal stiffening, (3) the vibratory level under aerodynamic forced response, and (4) the vibratory levels when unilateral contact occurs. Significant improvements of the final blade design are found: the need for an early integration of nonlinear structural interactions criteria in the design stage of modern aircraft engines components is highlighted.

scholarly journals Aeroelastic assessment of a highly loaded high pressure compressor exposed to pressure gain combustion disturbances

2018 ◽  
Vol 2 ◽  
pp. F72OUU
Author(s):  
Victor Bicalho Civinelli de Almeida ◽  
Dieter Peitsch
Keyword(s):  
High Pressure ◽  
Gas Turbines ◽  
Forced Response ◽  
Thermodynamic Efficiency ◽  
Efficiency Gain ◽  
Aerodynamic Damping ◽  
High Pressure Compressor ◽  
Pressure Gain Combustion ◽  
Pressure Compressor ◽  
Highly Loaded

A numerical aeroelastic assessment of a highly loaded high pressure compressor exposed to flow disturbances is presented in this paper. The disturbances originate from novel, inherently unsteady, pressure gain combustion processes, such as pulse detonation, shockless explosion, wave rotor or piston topping composite cycles. All these arrangements promise to reduce substantially the specific fuel consumption of present-day aeronautical engines and stationary gas turbines. However, their unsteady behavior must be further investigated to ensure the thermodynamic efficiency gain is not hindered by stage performance losses. Furthermore, blade excessive vibration (leading to high cycle fatigue) must be avoided, especially under the additional excitations frequencies from waves traveling upstream of the combustor. Two main numerical analyses are presented, contrasting undisturbed with disturbed operation of a typical industrial core compressor. The first part of the paper evaluates performance parameters for a representative blisk stage with high-accuracy 3D unsteady Reynolds-averaged Navier-Stokes computations. Isentropic efficiency as well as pressure and temperature unsteady damping are determined for a broad range of disturbances. The nonlinear harmonic balance method is used to determine the aerodynamic damping. The second part provides the aeroelastic harmonic forced response of the rotor blades, with aerodynamic damping and forcing obtained from the unsteady calculations in the first part. The influence of blade mode shapes, nodal diameters and forcing frequency matching is also examined.

Comparison of Fluid-Structure Coupling Methods for Blade Forced Response Prediction

2012 ◽  
Author(s):  
Florent Payer ◽  
Pascal Ferrand ◽  
Alain Dugeai ◽  
Fabrice Thouverez
Keyword(s):  
Transient State ◽  
Response Prediction ◽  
Forced Response ◽  
High Pressure Compressor ◽  
Time Marching ◽  
Aerodynamic Field ◽  
Decoupled Method ◽  
Marching Scheme ◽  
Pressure Compressor ◽  
Good Agreement

A time-marching coupled method has been applied to a high pressure compressor forced response case. The purpose of the study is to compare the contribution of the coupled scheme against the state of the art decoupled methodology. Although the time-marching scheme allows for a stronger coupling between the motion and aerodynamic field, results have shown good agreement with the decoupled method. The additional computing cost arising from the long transient state and the small difference in amplitude prediction with the decoupled scheme reduce the interest for the coupled one. A new transient state method is proposed to combine both coupled and decoupled schemes features. Here, the forcing and damping functions are extracted during the mechanical transient state of the coupled simulation and forced response is calculated as in the decoupled method. Results have shown good agreements with the experiment and all the methods are compared in terms of underlying assumptions and performances.

An Inverse Approach to Identify Tuned Aerodynamic Damping, System Frequencies and Mistuning: Part 3 — Application to Engine Data

2019 ◽  
Author(s):  
Felix Figaschewsky ◽  
Arnold Kühhorn ◽  
Bernd Beirow ◽  
Thomas Giersch ◽  
Sven Schrape ◽  
...  
Keyword(s):  
Equations Of Motion ◽  
Travelling Wave ◽  
Forced Response ◽  
Aerodynamic Damping ◽  
Inverse Approach ◽  
Novel Approach ◽  
High Pressure Compressor ◽  
Blade Tip ◽  
Identification Approach ◽  
Reference Measurements

Abstract A novel approach for the identification of tuned aerodynamic damping, system frequencies, forcing and mistuning has been introduced in the first part of this paper. It is based on the forced response equations of motion for a blade dominated mode family. A least squares formulation allows to identify the system’s parameters directly from measured frequency response functions (FRFs) of all blades recorded during a sweep through a resonance. The second part has dealt with its modification and application to experimental modal analyses of blisks at rest. This 3rd part aims at presenting the application of the approach to blade tip timing (BTT) data acquired in rig tests. Therefore, blisk rotors of two different engines are studied: a single stage fan rig and a 4.5 stage high pressure compressor (HPC) rig. The rig test campaign of the fan blisk included also an intentional mistuning experiment that allows to study the performance of the identification approach for a similar rotor with two different mistuning levels. It is demonstrated that the approach can identify aerodynamic damping curves, system frequencies, mistuning pattern and forced travelling wave modes (TWMs) from state of the art BTT data monitored during rig or engine tests. All derived mistuning patterns could be verified with reference measurements at standstill. The derived aerodynamic damping curves and system frequencies show a reasonable agreement with simulations. For the HPC case a multitude of excited TWMs could be identified which also lines up with previous simulations.

A Test Rig for Non-Contact Travelling Wave Excitation of a Bladed Disk With Underplatform Dampers

2010 ◽  
Author(s):  
Teresa Berruti ◽  
Christian M. Firrone ◽  
Muzio M. Gola
Keyword(s):  
Numerical Models ◽  
Experimental Tests ◽  
Calibration Procedure ◽  
Travelling Wave ◽  
Forced Response ◽  
Wave Excitation ◽  
Test Rig ◽  
Response Measurement ◽  
Static Test ◽  
Bladed Disk

The paper presents a static test rig called “Octopus” designed for the validation of numerical models aimed at calculating the nonlinear dynamic response of a bladed disk with underplatform dampers (UPDs). The test rig supports a bladed disk on a fixture and each UPD is pressed against the blade platforms by wires pulled by dead weights. Both excitation system and response measurement system are noncontacting. The paper features the design and the set-up of the noncontacting excitation generated by electromagnets placed under each blade. A travelling wave excitation is generated according to a desired engine order by shifting the phase of the harmonic force of one electromagnet with respect to the contiguous exciters. Since the friction phenomenon generated by UPDs introduces nonlinearities on the forced response, the amplitude of the exciting force must be kept constant at a known value on every blade during step-sine test to calculate Frequency Response Functions. The issue of the force control is therefore addressed since the performance of the electromagnet changes with frequency. The system calibration procedure and the estimated errors on the generated force are also presented. Examples of experimental tests that can be performed on a dummy integral bladed disk (blisk) mounted on the rig are described in the end.

Model update and validation of a mistuned high-pressure compressor blisk

2019 ◽  
Vol 123 (1260) ◽  
pp. 230-247 ◽  
Author(s):  
B. Beirow ◽  
A. Kühhorn ◽  
F. Figaschewsky ◽  
P. Hönisch ◽  
T. Giersch ◽  
...  
Keyword(s):  
High Pressure ◽  
Ambient Pressure ◽  
Pressure Gauge ◽  
Structural Models ◽  
Forced Response ◽  
Test Program ◽  
Maximum Information ◽  
High Pressure Compressor ◽  
The Impact ◽  
Pressure Compressor

ABSTRACTIn order to prepare an advanced 4-stage high-pressure compressor rig test campaign, details regarding both accomplishment and analysis of preliminary experiments are provided in this paper. The superior objective of the research project is to contribute to a reliable but simultaneously less conservative design of future high pressure blade integrated disks (blisk). It is planned to achieve trend-setting advances based on a close combination of both numerical and experimental analyses. The analyses are focused on the second rotor of this research compressor, which is the only one being manufactured as blisk. The comprehensive test program is addressing both surge and forced response analyses e.g. caused by low engine order excitation. Among others the interaction of aeroelastics and blade mistuning is demanding attention in this regard. That is why structural models are needed, allowing for an accurate forced response prediction close to reality. Furthermore, these models are required to support the assessment of blade tip timing (BTT) data gathered in the rig tests and strain gauge (s/g) data as well. To gain the maximum information regarding the correlation between BTT data, s/g-data and pressure gauge data, every blade of the second stage rotor (28 blades) is applied with s/g. However, it is well known that s/g on blades can contribute additional mistuning that had to be considered upon updating structural models.Due to the relevance of mistuning, efforts are made for its accurate experimental determination. Blade-by-blade impact tests according to a patented approach are used for this purpose. From the research point of view, it is most interesting to determine both the effect s/g-instrumentation and assembling the compressor stages on blade frequency mistuning. That is why experimental mistuning tests carried out immediately after manufacturing the blisk are repeated twice, namely, after s/g instrumentation and after assembling. To complete the pre-test program, the pure mechanical damping and modal damping ratios dependent on the ambient pressure are experimentally determined inside a pressure vessel. Subsequently the mistuning data gained before is used for updating subset of nominal system mode (SNM) models. Aerodynamic influence coefficients (AICs) are implemented to take aeroelastic interaction into account for forced response analyses. Within a comparison of different models, it is shown for the fundamental flap mode (1F) that the s/g instrumentation significantly affects the forced response, whereas the impact of assembling the compressor plays a minor role.

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