Experimental Investigation of Forced Response Impeller Blade Vibration in a Centrifugal Compressor With Variable Inlet Guide Vanes: Part 1—Blade Damping

Zemp, Armin; Abhari, Reza S.; Ribi, Beat

doi:10.1115/gt2011-46289

Cited by 6 publications

(5 citation statements)

References 28 publications

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“…Zemp et al [21,22] conducted an experimental investigation of the forced response of impeller blade vibration in a centrifugal compressor with variable inlet guide vanes in two parts: (1) blade damping and (2) forcing function and FSI computations. Zhou et al [23] studied the forced response prediction for the last stage of the steam turbine blade, subject to low engine order excitation.…”

Section: Review Of Related Literaturementioning

confidence: 99%

A Study on Fluid Self‐Excited Flutter and Forced Response of Turbomachinery Rotor Blade

Hsu

2014

Mathematical Problems in Engineering

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Complex mode and single mode approach analyses are individually developed to predict blade flutter and forced response. These analyses provide a system approach for predicting potential aeroelastic problems of blades. The flow field properties of a blade are analyzed as aero input and combined with a finite element model to calculate the unsteady aero damping of the blade surface. Forcing function generators, including inlet and distortions, are provided to calculate the forced response of turbomachinery blading. The structural dynamic characteristics are obtained based on the blade mode shape obtained by using the finite element model. These approaches can provide turbine engine manufacturers, cogenerators, gas turbine generators, microturbine generators, and engine manufacturers with an analysis system to remedy existing flutter and forced response methods. The findings of this study can be widely applied to fans, compressors, energy turbine power plants, electricity, and cost saving analyses.

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Section: Review Of Related Literaturementioning

confidence: 99%

A Study on Fluid Self‐Excited Flutter and Forced Response of Turbomachinery Rotor Blade

Hsu

2014

Mathematical Problems in Engineering

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“…In the first part of this paper the influence of the inlet guide vane angle setting and the operating point on the forcing function will be detailed. The measurements of the distorted inlet flow field presented in Part 1 [22] of this two-part paper were used as inlet boundary conditions for a series of 3D unsteady CFD simulations. The calculated amplitudes and phase angles of the unsteady loads were compared to the measured values.…”

Section: Motivation and Scope Of The Papermentioning

confidence: 99%

Experimental Investigation of Forced Response Impeller Blade Vibration in a Centrifugal Compressor With Variable Inlet Guide Vanes: Part 2—Forcing Function and FSI Computations

Zemp

Abhari

Schleer

2011

Volume 6: Structures and Dynamics, Parts a and B

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As the second part of a two-part paper, this paper presents an experimental investigation of forced response impeller blade vibrations in a centrifugal compressor stage caused by variable inlet guide vanes. Although it is common practice to experimentally test the forced response blade vibration behavior of new impeller designs in terms of strain gauge or tip-timing measurements, the impact of the unsteady blade pressure distribution acting as an unsteady load on the blade surfaces is still not known. A centrifugal compressor impeller was therefore instrumented with dynamic strain gauges and fast-response pressure transducers to measure the forcing of the impeller blades for different compressor operating points and various inlet guide vane angle settings. The results showed a decrease in the excitation amplitudes for reduced mass flow rates of the compressor stage. The inlet guide vane angle setting affected the convection speed of the distortion pattern along the blade surface. An increase in the negative inlet guide vane angle caused higher excitation amplitudes especially in the inducer part of the blade. However, the largest negative inlet guide vane setting caused the smallest excitation amplitudes as this setup introduced the smallest amount of inlet distortion to the inlet flow field. A series of unidirectional fluid structure interaction calculations was performed to show the limitations and requirements of today’s numerical tools.

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“…Good agreement was obtained with the material damping extrapolated from measurements performed under aerodynamic excitation for decreasing inlet pressure values. In [10], with a specific engine representative of operating conditions, analogous tests revealed that aerodynamic damping could be about 3 times higher than material damping, then the latter is far from negligible.…”

Section: Introductionmentioning

confidence: 99%

Modal Tests and Analysis of a Radial Impeller at Rest: Influence of Surrounding Air on Damping

Gibert

Blanc

Almeida

et al. 2012

Volume 7: Structures and Dynamics, Parts a and B

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HCF risk assessment for turbomachinery blades requires the prediction of vibratory levels, which in turn requires fine damping quantification. This issue is especially sensitive for structures with low structural damping such as monobloc centrifugal compressor disks (blisks). The material composing blisks and aero-dynamic flow both contribute to damping phenomena. A strategy for non-aerodynamic damping characterization is to perform experiments in vacuum. This paper focuses on the use of modal tests in vacuum to estimate material damping under non-rotating conditions. Experiments are performed on an isolated impeller manufactured from a single piece in a vacuum chamber at different air pressure levels ranging from 10 mbar to 1 bar. Strong dependency of damping ratios on pressure can be found on the first flexural mode, leading to two types of application. Firstly, measurements enable assessing the validity of extrapolations of non-aerodynamic damping from measurements sometimes performed under less thorough vacuum conditions. Basic fluid-structure interaction models are used to interpret and quantify the evolution of modal quantities when air is progressively removed. Secondly, vacuum measurements can give frequency response functions (FRFs) with much greater separation between resonance peaks. In this study, the damping ratio found in vacuum condition are 3% of these at ambient pressure corresponding to a magnitude 30dB higher at resonance peaks. This contrasts with in-air measurements on cyclic symmetry structures, like blisks, with high modal density that make the direct interpretation of FRFs and their modal analysis more difficult.

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Experimental Investigation of Forced Response Impeller Blade Vibration in a Centrifugal Compressor With Variable Inlet Guide Vanes: Part 1—Blade Damping

Cited by 6 publications

References 28 publications

A Study on Fluid Self‐Excited Flutter and Forced Response of Turbomachinery Rotor Blade

A Study on Fluid Self‐Excited Flutter and Forced Response of Turbomachinery Rotor Blade

Experimental Investigation of Forced Response Impeller Blade Vibration in a Centrifugal Compressor With Variable Inlet Guide Vanes: Part 2—Forcing Function and FSI Computations

Modal Tests and Analysis of a Radial Impeller at Rest: Influence of Surrounding Air on Damping

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