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

The conventional resonance conditions are derived based on the conventionally designed impellers without splitter blades. This paper proposes the resonance conditions for impellers under the excitation from the impeller–diffuser interaction with attention paid on the influence of splitter blades. A lumped parameter model is established and the modal analysis is carried out. The blade-based representative modal vector (RMV) is defined. The influence of splitter blades on the impeller’s traits of modes is investigated by analyzing the spatial harmonic contents of the RMV. Then, given the specific form of the diffuser-induced engine order excitation acting on the main and splitter blades, the resonance conditions are derived. Tuned and mistuned cases are provided for a practical impeller. The resonance conditions are verified by harmonic response calculations. The applications of the proposed resonance conditions in resonance identification and hazard evaluation of different excitations are given. The differences between the proposed resonance conditions and the conventional ones are discussed. The research indicates that even the RMV of the tuned impeller contains two harmonic components due to the existence of splitter blades. When the excitation frequency equals the natural frequency of the impeller and the excitation order matches with either harmonic index of the two harmonics, the resonance occurs. The results of case studies show that the harmfulness of various engine orders of excitation can be exactly evaluated by the joint use of the spatial harmonic contents analysis result and the proposed resonance conditions; however, analyzing based on the conventional resonance conditions may lead to the misjudgment of the harmfulness of the excitations.

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“…Then, the spatial harmonic contents analysis is performed on it. Bi can be represented as Equation (9).…”

Section: Spatial Harmonic Contents Analysis To the Rmvmentioning

confidence: 99%

“…Research shows that adding splitter blades not only helps reduce blade loadings but also can improve the compressor performance [4][5][6]. Thus, the impellers with splitter blades are more and more used in engineering [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Investigation of the Influence of Splitter Blades on the Resonance Conditions of Impellers

Liu

Cheng

2019

Applied Sciences

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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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“…In the second part of this two part publication [19] the investigation focused on the evolution of the forcing function. The change in the unsteady blade pressure distribution was measured with blade-mounted fast-response pressure sensors.…”

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 1—Blade Damping

Zemp

Abhari

Ribi³

2011

Volume 6: Structures and Dynamics, Parts a and B

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Forming the first part of a two-part paper, the quantification of the resonant response levels and the damping quantities for a centrifugal compressor impeller with variable inlet guide vanes under engine representative operating conditions is detailed in this work. The motivation for the investigation is the lack of experimental data that are needed to improve and validate computational tools used during the design phase. Measurements were performed during resonant blade vibrations with the inlet pressure, the inlet guide vane angle and the operating point as the varying parameters. The flow non-uniformity introduced into the inlet flow field was measured with an aerodynamic probe. These measurements showed an increase in flow distortion for increased guide vane angles. The response amplitudes were acquired with dynamic strain gauges. A curve-fit method was applied to estimate the critical damping ratios. The results showed a linear correlation of the aerodynamic damping with the inlet pressure. The mode dependent material damping was therefore derived using a linear extrapolation to vacuum conditions of the inlet pressure dependent overall damping. The resonant blade dynamics could be captured with a single degree of freedom model. The aerodynamic damping and the maximum strain response were found to significantly depend on the inlet guide vane angle setting and on the throttle setting of the compressor.

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

Cited by 5 publications

References 29 publications

Investigation of the Influence of Splitter Blades on the Resonance Conditions of Impellers

Investigation of the Influence of Splitter Blades on the Resonance Conditions of Impellers

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 1—Blade Damping

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