Refined Effects in Turbomachinery Blade Vibrations

1987 ◽  
pp. 373-382
Author(s):  
H. Irretier ◽  
S. Janecki
Keyword(s):  
Blade Vibrations

Actively controlling a rotating blade vibrations excited by a superharmonic force

2018 ◽  
Vol 27 (2) ◽  
pp. 321-332
Author(s):  
Ali Kandil ◽  
M. Eissa ◽  
M. Kamel ◽  
W. El-Ganaini ◽  
H. El-Gohary
Keyword(s):  
Rotating Blade ◽  
Blade Vibrations

Sparse Reconstruction Method of Non-Uniform Sampling and its Application in Blade Tip Timing System

2020 ◽  
Author(s):  
Jie Tian ◽  
Xiaopu Zhang ◽  
Yong Chen ◽  
Peter Russhard ◽  
Hua Ouyang
Keyword(s):  
Compressive Sensing ◽  
Sparse Reconstruction ◽  
Reconstruction Method ◽  
Blade Vibration ◽  
Uniform Sampling ◽  
Blade Vibrations ◽  
Timing Data ◽  
Blade Tip ◽  
Simultaneous Identification ◽  
Multi Mode

Abstract Based on the blade vibration theory of turbomachinery and the basic principle of blade timing systems, a sparse reconstruction model is derived for the tip timing signal under an arbitrary sensor circumferential placement distribution. The proposed approach uses the sparsity of the tip timing signal in the frequency domain. The application of compressive sensing in reconstructing the blade tip timing signal and monitoring multi-mode blade vibrations is explored. To improve the reconstruction effect, a number of numerical experiments are conducted to examine the effects of various factors on synchronous and non-synchronous signals. This enables the specific steps involved in the compressive sensing reconstruction of tip timing signals to be determined. The proposed method is then applied to the tip timing data of a 27-blade rotor. The results show that the method accurately identifies the multi-mode blade vibrations at different rotation speeds. The proposed method has the advantages of low dependence on prior information, insensitivity to environmental noise, and simultaneous identification of synchronous and non-synchronous signals. The experimental results validate the effectiveness of the proposed approach in engineering applications.

Investigation of Fan Blades Vibration due to Blade/Casing Rubbing Interactions Using In-Plane Two-Dimensional Model

2018 ◽  
Author(s):  
Jiaguangyi Xiao ◽  
Yong Chen ◽  
Hua Ouyang ◽  
Anjenq Wang
Keyword(s):  
Travelling Waves ◽  
Golden Section ◽  
Contact Forces ◽  
Two Dimensional ◽  
Rotating Speed ◽  
Bladed Disk ◽  
Speed Range ◽  
Blade Vibrations ◽  
Blade Tip ◽  
External Forces

Interactions between casings and bladed-disks of modern turbofan engines may occur through various mechanisms: casing distortions, rotor vibrations and casing vibrations to name a few. These interactions might lead to nonlinear blade vibrations, which could then induce severe damages to both structures. The impacts of casing vibrations on the vibration behaviors of engine blades are studied in this paper. A two-dimensional in-plane model is established in this paper. Fan blade, disk and casing are modeled using beam element. Craig-Bampton model reduction is applied to simplify the model. Penalty method mixed with golden section method is created and used for contact treatments. The interaction is initiated by the external forces acting on the casing. The casing is excited to two-, three- and four-nodal diameter vibration patterns, respectively. In order to capture the core of the problem, contact forces applied to the casing, and casing damping are neglected. Steady casing vibrations could thus be generated. Blade vibrations are calculated in a wide rotating speed range, maximum amplitudes are recorded and studied. The results show that the bladed-disk will have several vibration peaks in the calculated rotating speed range. To figure out the physical mechanisms of these peaks, Fourier spectrums as well as different bladed-disk materials are introduced. Almost all vibration peaks can be explained by three kinds of mechanisms found and summarized in this paper. Two of them are related to travelling waves and the third is related to harmonics. Speed and frequency margins that are related to blade-tip-rub induced vibrations are defined and analyzed. The findings and ideas shown in this paper can be used as a reference in engine preliminary structural design to avoid potential blade tip-rub induced damages.

Acoustic Resonance in an Axial Multistage Compressor Leading to Non-Synchronous Blade Vibration

2020 ◽  
Author(s):  
Anne-Lise Fiquet ◽  
Agathe Vercoutter ◽  
Nicolas Buffaz ◽  
Stéphane Aubert ◽  
Christoph Brandstetter
Keyword(s):  
Acoustic Waves ◽  
High Speed ◽  
Numerical Study ◽  
Acoustic Resonance ◽  
Structural Vibration ◽  
Wave Number ◽  
Blade Vibration ◽  
Acoustic Modes ◽  
Blade Vibrations ◽  
Circumferential Wave

Abstract Significant non-synchronous blade vibrations (NSV) have been observed in an experimental three-stage high-speed compressor at part-speed conditions. High amplitude acoustic modes, propagating around the circumference and originating in the highly loaded Stage-3 have been observed in coherence with the structural vibration mode. In order to understand the occurring phenomena, a detailed numerical study has been carried out to reproduce the mechanism. Unsteady full annulus RANS simulations of the whole setup have been performed using the solver elsA. The results revealed the development of propagating acoustic modes which are partially trapped in the annulus and are in resonance with an aerodynamic disturbance in Rotor-3. The aerodynamic disturbance is identified as an unsteady separation of the blade boundary layer in Rotor-3. The results indicate that the frequency and phase of the separation adapt to match those of the acoustic wave, and are therefore governed by acoustic propagation conditions. Furthermore, the simulations clearly show the modulation of the propagating wave with the rotor blades, leading to a change of circumferential wave numbers while passing the blade row. To analyze if the effect is self-induced by the blade vibration, a noncoherent structural mode has been imposed in the simulations. Even at high vibration amplitude the formerly observed acoustic mode did not change its circumferential wave number. This phenomenon is highly relevant to modern compressor designs, since the appearance of the axially propagating acoustic waves can excite blade vibrations if they coincide with a structural eigenmode, as observed in the presented experiments.

Numerical investigation of rub-induced composite fan blade vibrations and abradable coating removals

2019 ◽  
Vol 226 ◽  
pp. 111274 ◽  
Author(s):  
Jia-Guang-Yi Xiao ◽  
Yong Chen ◽  
Jie Tian ◽  
Hua Ou-Yang ◽  
Anjenq Wang
Keyword(s):  
Numerical Investigation ◽  
Abradable Coating ◽  
Blade Vibrations ◽  
Fan Blade

On the Importance of Shear Deformation, Rotatory Inertia, and Coriolis Forces in Turbine Blade Vibrations

1986 ◽  
Vol 108 (2) ◽  
pp. 319-324 ◽  
Author(s):  
K. A. Ansari
Keyword(s):  
Shear Deformation ◽  
Turbine Blade ◽  
Normal Modes ◽  
Functional Method ◽  
Lumped Parameter Model ◽  
Rotatory Inertia ◽  
Blade Vibration ◽  
Coriolis Forces ◽  
Analysis Technique ◽  
Blade Vibrations

This paper is concerned with the significance of the effects of shear deformation, rotatory inertia, and Coriolis forces in the analysis of turbine blade vibrations. Since these are quite pronounced at the high frequency ranges encountered in turbine blade vibration problems, they should not be overlooked although their inclusion paves the way for a complicated nonlinear analysis. An approximate analysis technique is presented which involves an application of the stationary functional method using the normal modes of a discretized model. Numerical results for a typical blade are obtained and discussed. An advantage of this analysis as applied to a lumped parameter model is that nonlinear modes higher than the fundamental can also be easily computed and assessed.

Naval Centrifugal Compressor Design Using CAD Solutions

2014 ◽  
Vol 658 ◽  
pp. 59-64
Author(s):  
Constantin Dumitrache ◽  
Ioan Calimanescu ◽  
Corneliu Comandar
Keyword(s):  
High Flow ◽  
Mean Stress ◽  
Aerodynamic Optimization ◽  
Aerodynamic Forces ◽  
Dynamic Stresses ◽  
Unsteady Aerodynamic ◽  
Wide Range ◽  
Compressor Design ◽  
Blade Vibrations ◽  
Centrifugal Loading

Centrifugal compressors of turbochargersoperate in a wide range of rotational speeds, which depends on the load of the supercharged engine. Current designs of turbocharger compressors exhibit high efficiencies accompanied by high flow capacities [1]. Consequences of aerodynamic optimization are high mean stress values in the blades due to centrifugal loading as well as dynamic stresses due to blade vibrations. Blade vibrations in a turbocharger compressor are assumed to be predominantly excited by unsteady aerodynamic forces [2]. These forces are caused by a variety of sources influencing the flow. Examples include the geometry of the flow channel, elbows, the diffuser vanes or struts. Therefore, an understanding of FSI is essential for further design optimizations.

Analyzing rotor-blade vibrations in gas-turbine units

1983 ◽  
Vol 15 (5) ◽  
pp. 636-642
Author(s):  
E. A. Igumentsev
Keyword(s):  
Gas Turbine ◽  
Rotor Blade ◽  
Blade Vibrations
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