Method for Predicting Unsteady Vibration of Gas Turbine Compressor Blades Under Subsonic Near-Stall Conditions

2014 ◽  
Vol 136 (12) ◽  
Author(s):  
Kazuyuki Yamaguchi ◽  
Yasuo Takahashi
Keyword(s):  
Gas Turbine ◽  
Incidence Angle ◽  
Low Frequency ◽  
Frequency Component ◽  
Compressor Blades ◽  
Element Analysis ◽  
Blade Vibration ◽  
Simple Method ◽  
Frequency Components ◽  
Gas Turbine Compressor

Wind tunnel tests and numerical calculations using computational fluid dynamics (CFD) analysis and structural finite element analysis were conducted to clarify the vibration characteristics of gas turbine compressor blades under subsonic near-stall conditions. The results show that discrete low-frequency components of pressure are created by variation of the separation region and that discrete high-frequency components are created by vortex shedding when the compressor blade incidence angle is in the stall region. The natural frequency component resonated by the random fluid force is dominant in blade vibration. The numerically calculated phenomena agree well with the measured phenomena. The vibration amplitude increases with the incidence angle and the Mach number, and it increases rapidly at higher angles. A simple method for predicting the vibration stress using static calculations is reasonably accurate.

Unsteady Vibration of a Gas Turbine Compressor Blade at Subsonic Near-Stall Conditions

2013 ◽  
Author(s):  
Kazuyuki Yamaguchi ◽  
Yasuo Takahashi
Keyword(s):  
Mach Number ◽  
Modal Analysis ◽  
Natural Frequency ◽  
Damping Ratio ◽  
Three Dimensional ◽  
Low Frequency ◽  
Frequency Component ◽  
Blade Vibration ◽  
Aerodynamic Damping ◽  
Frequency Components

Cascade wind tunnel tests were conducted to clarify unsteady blade vibration characteristics near stall conditions. An oscillating strain and pressure on a blade surface were measured. An aerodynamic damping ratio was also measured using the sweep excitation method and the operational modal analysis. Moreover, an unsteady blade vibration response and aerodynamic damping ratios were calculated using a three-dimensional computational fluid dynamics and a three-dimensional structural finite element method. As a result of the experiments, the natural frequency component oscillated by the broadband frequency component of the fluid force was dominant in the stress, while the discrete low frequency components appeared in the pressure. The amplitudes of the stress and pressure increased when the Mach number or the incidence increased. As a result of the calculations, the discrete low frequency components appeared in the pressure, and those components and the natural frequency components appeared in the stress. The experimental and calculation results of the stress amplitude were generally in agreement. The measured damping ratios increased when the Mach number increased. The dispersion of the measured damping ratio using the operational modal analysis was small. The calculated damping ratio was 1.3–1.8 times larger than the measured result.

A Statistical Study on HCF Validation Data for Axial Gas Turbine Compressor Blades

2021 ◽  
Author(s):  
Lukas Schuchard ◽  
Stefano Cerutti ◽  
Matthias Voigt ◽  
Ronald Mailach
Keyword(s):  
Gas Turbine ◽  
Statistical Study ◽  
Compressor Blades ◽  
Validation Data ◽  
Gas Turbine Compressor

Failure Investigation of Frame 6FA Gas Turbine Compressor Blades

2015 ◽  
Vol 69 (2) ◽  
pp. 647-651 ◽  
Author(s):  
M. Swamy ◽  
Kulvir Singh ◽  
A. H. V. Pavan ◽  
Antony Harison M. C. ◽  
G. Jayaraman
Keyword(s):  
Gas Turbine ◽  
Compressor Blades ◽  
Failure Investigation ◽  
Gas Turbine Compressor

Determination of Vibration Amplitudes and Stresses Using the Holography Interference Techniques and Finite Element Method

1983 ◽  
Vol 105 (4) ◽  
pp. 484-488 ◽  
Author(s):  
Z. F. Fu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Gas Turbine ◽  
Strain Gage ◽  
Present Method ◽  
The Finite Element Method ◽  
Compressor Blades ◽  
Gas Turbine Compressor ◽  
Element Method

A new method which combines the holography interference technique with the finite element method for determining the distribution of vibration amplitudes and stresses of gas turbine compressor blades is presented in this paper. In comparison with the ordinary electrical strain gage method, the present method has the advantage that there is no limitation to the number of measuring points and good results can be obtained even at high order modes.

Vibration Amplitudes of Compressor Blades Resulting From Scatter in Blade Natural Frequencies

1969 ◽  
Vol 91 (3) ◽  
pp. 182-187 ◽  
Author(s):  
R. C. F. Dye ◽  
T. A. Henry
Keyword(s):  
Gas Turbine ◽  
Natural Frequency ◽  
Natural Frequencies ◽  
Model Analysis ◽  
Lumped Parameter Model ◽  
Compressor Blades ◽  
Lumped Parameter ◽  
Gas Turbine Compressor ◽  
Flexible Disk

Intercoupling between blades mounted on a flexible disk is examined employing a lumped-parameter model incorporating damping. Tests carried out on a gas turbine compressor and blades provide frequency and mass parameters for the model. Analysis of the model shows that vibration, and hence stress, in one or more blades, can be magnified if the distribution of blade natural frequency around the disk is suitably chosen. Feasible distributions are examined, leading to stress increases of up to 180 percent.

Aerodynamic Factors of Influence on the Resonance Vibration of Gas Turbine Compressor Blades

2015 ◽  
Vol 47 (5) ◽  
pp. 711-718 ◽  
Author(s):  
Yu. M. Tereshchenko ◽  
E. V. Doroshenko ◽  
A. Tehrani ◽  
J. Abolhassanzade
Keyword(s):  
Gas Turbine ◽  
Resonance Vibration ◽  
Compressor Blades ◽  
Factors Of Influence ◽  
Gas Turbine Compressor

Self-sustained low-frequency components in an impinging shear layer

1982 ◽  
Vol 116 ◽  
pp. 157-186 ◽  
Author(s):  
C. Knisely ◽  
D. Rockwell
Keyword(s):  
Shear Layer ◽  
Vortex Formation ◽  
Low Frequency ◽  
Frequency Component ◽  
Travelling Wave ◽  
Instability Wave ◽  
Spectral Content ◽  
Frequency Components ◽  
The Subject ◽  
Amplitude Growth

Oscillations of a cavity shear layer, involving a downstream-travelling wave and associated vortex formation, its impingement upon the cavity corner, and upstream influence of this vortex-corner interaction are the subject of this experimental investigation.Spectral analysis of the downstream-travelling wave reveals low-frequency components having substantial amplitudes relative to that of the fundamental (instability) frequency component; using bicoherence analysis it is shown that the lowest-frequency component can interact with the fundamental either to reinforce itself or to produce an additional (weaker) low-frequency component. In both cases, all frequency components exhibit an overall phase difference of almost 2kπ(k = 1, 2,…) between separation and impingement. Furthermore, the low-frequency and fundamental components have approximately the same amplitude growth rates and phase speeds; this suggests that the instability wave is amplitude-modulated at the low frequency, as confirmed by the form of instantaneous velocity traces.At the downstream corner of the cavity, successive vortices, arising from the amplified instability wave, undergo organized variations in (transverse) impingement location, producing a low-frequency component(s) of corner pressure. The spectral content and instantaneous trace of this impingement pressure are consistent with those of velocity fluctuations near the (upstream) shear-layer separation edge, giving evidence of the strong upstream influence of the corner region.

Continuous, on-line, real-time spectral analysis of SAP signals during cardiopulmonary bypass

1995 ◽  
Vol 268 (6) ◽  
pp. H2329-H2335
Author(s):  
M. W. Yang ◽  
T. B. Kuo ◽  
S. M. Lin ◽  
K. H. Chan ◽  
S. H. Chan
Keyword(s):  
Spectral Analysis ◽  
Cardiopulmonary Bypass ◽  
Blood Vessels ◽  
Real Time ◽  
Low Frequency ◽  
Frequency Component ◽  
Very Low Frequency ◽  
Frequency Components ◽  
On Line ◽  
Very High

We communicated the application of continuous, on-line, real-time power spectral analysis of systemic arterial pressure (SAP) signals during cardiopulmonary bypass when the heart was functionally but reversibly disconnected from the blood vessels. Based on observations from 15 cases of successfully completed coronary artery bypass grafting procedures, we found that the very low (0.00-0.08 Hz), low (0.08-0.15 Hz)-, high (0.15-0.25 Hz)-, and very high (0.80-1.60 Hz) frequency components of SAP signals exhibited differential changes before, during, and after cardiopulmonary bypass. In particular, the very low-frequency component, which purportedly represents the contribution of vasomotor activity to SAP, presented only a mild decrease in power during hypothermic cardioplegia. Interestingly, the total peripheral resistance also manifested only a slight reduction during the same period. On the other hand, the low-, high-, and very high frequency components were essentially eliminated. These results unveiled an active role for the blood vessels in the maintenance of SAP during cardiopulmonary bypass, possibly as a result of a maintained vasomotor tone as reflected by the sustained very low frequency component of the SAP signals.

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