Computer Aided Analysis of Turbine Blade Vibration Test Data

1973 ◽  
Vol 6 (3) ◽  
pp. 123-128
Author(s):  
F. L. N-Nagy ◽  
S. R. Taylor
Keyword(s):  
Vibration Amplitude ◽  
Digital Form ◽  
Test Rig ◽  
Blade Vibration ◽  
Campbell Diagram ◽  
Vibration Data ◽  
Computer Aided Analysis ◽  
On Line ◽  
Analogue To Digital ◽  
Visual Record

A pilot system has been developed which automatically scans and evaluates experimental vibration data obtained from a test rig replica of a bladed wheel of a turbine in service. High vibration amplitude signals are selected for further analysis. This data is converted into digital form using an analogue to digital converter and is processed in a digital computer suitably programmed for harmonic analysis. The results are plotted on a Campbell Diagram using an on-line digital X-Y plotter which gives a visual record of the most salient information from the tests in a readily interpreted form. The paper describes the equipment used, the method of converting the analogue-type signals to digital form, analyses the accuracy of the conversion method, and gives the reasons for undertaking such vibration analysis.

Experimental determination of IGV preswirl effect on impeller blade vibration in an unshrouded centrifugal compressor

2021 ◽  
pp. 095765092110247
Author(s):  
Xinwei Zhao ◽  
Hongkun Li ◽  
Shuhua Yang ◽  
Zhenfang Fan ◽  
Yang Wang
Keyword(s):  
Dynamic Stress ◽  
Operating Conditions ◽  
Large Shift ◽  
Blade Vibration ◽  
Impeller Blade ◽  
Inlet Flow ◽  
Vibration Data ◽  
Aerodynamic Loading ◽  
High Dynamic

The unshrouded impeller is widely used in industrial centrifugal compressors and normally operates at high tip speed and large volume flow. However, this type of impeller can be very sensitive to flow excitations such as IGV wake, and hence encounters the challenge of high dynamic stress. Due to the lack of experimental vibration data, this paper aims to enhance the understanding of the IGV preswirl effect. The real operating representative data from strain gauges is acquired during the experiment. The blade transient and quasi-steady response due to upstream IGV wake under different configurations are investigated and quantified. Results show that the blade response increases with larger positive regulation. And under specific operating conditions, the vibration of the blade is quite large, which is comparable with synchronize resonance. This increment is attributed to the aerodynamic loading change due to enhanced distortion of the inlet flow. Based on the current findings, accurate numerical prediction of the blade forced vibration for a large shift of inlet flow condition is also needed for more reliable operating of the impeller.

Monitoring Offshore Pipelines Using Forced Transverse Vibration: Data Analysis

1995 ◽  
Author(s):  
Hugh E. M. Hunt
Keyword(s):  
Fluid Flow ◽  
Data Analysis ◽  
Transverse Vibration ◽  
Vibration Amplitude ◽  
Support Condition ◽  
Offshore Pipelines ◽  
Vibration Data ◽  
Wavelet Methods

Abstract Vibration methods are used to identify faults, such as spanning and loss of cover, in long off-shore pipelines. A pipeline ‘pig’, propelled by fluid flow, generates transverse vibration in the pipeline and the measured vibration amplitude reflects the nature of the support condition. Large quantities of vibration data are collected and analysed by Fourier and wavelet methods.

New Step to Improve the Accuracy of Blade Synchronous Vibration Parameters Identification Based on Combination of GARIV and LM Algorithm

2017 ◽  
Author(s):  
Weimin Wang ◽  
Sanqun Ren ◽  
Shan Huang ◽  
Qihang Li ◽  
Kang Chen
Keyword(s):  
Experimental Study ◽  
Parameters Identification ◽  
Least Square ◽  
Experimental Result ◽  
Blade Vibration ◽  
Vibration Displacement ◽  
Campbell Diagram ◽  
Identification Method ◽  
Blade Tip ◽  
Vibration Parameters

Generally, turbine blade vibration can be divided into asynchronous vibration and synchronous vibration. Comparing to parameters identification of asynchronous vibration, that of the synchronous vibration is more difficult and needs more sensors. The applicability of the synchronous identification method is more stringent than that of asynchronous identification method. A new method is presented to identify the blade synchronous vibration parameters based on the blade tip-timing (BTT) method and previous achievements in this region. Here, the parameters, such as the frequency of harmonic resonance center, blade vibration amplitude and the initial phase, are obtained by the nonlinear least square fitting algorithm based on relationships between the rotation speed and the blade tip displacement. We call this way as sweep frequency fitting (SFF) method. As the blade is operated at a constant speed that is near the frequency of resonance center, the blade vibration displacement can be obtained by the sensors at different positions, so the blade synchronous vibration Engine Order (EO) can be obtained by the global autoregressive with instrumental variables (GARIV) method. Furthermore the Campbell diagram of blade synchronous vibration can be plotted by the parameters obtained by GARIV method and SFF method. In the experimental study, the parameter identification of blade synchronous vibration is completed and the Campbell diagram of blade vibration is accurately plotted under the excitation of six magnets. Meanwhile, the experimental study and analysis on the harmonic vibration of blade with different numbers of excitation are carried out. The relative deviation of the dynamic frequency of blade between the experimental result and simulation result is less than 1%.

scholarly journals A Nonintrusive Rotor Blade Vibration Monitoring System

1996 ◽  
Author(s):  
Henry Jones
Keyword(s):  
Rotor Blade ◽  
Rotating Machinery ◽  
Vibration Monitoring ◽  
Static Deflection ◽  
Blade Vibration ◽  
Turbine Engine ◽  
Measurement Systems ◽  
Timing Data ◽  
On Line ◽  
Engine Rotor

A technique for measuring turbine engine rotor blade vibrations has been developed as an alternative to conventional strain-gage measurement systems. Light probes are mounted on the periphery of the engine rotor casing to sense the precise blade passing times of each blade in the row. The timing data are processed on-line to identify (1) individual blade vibration amplitudes and frequencies, (2) interblade phases, (3) system modal definitions, and (4) blade static deflection. This technique has been effectively applied to both turbine engine rotors and plant rotating machinery.

scholarly journals The methodology for measuring the vibration amplitude of the blade of the aircraft engine compressor in the fatigue test

Mechanik ◽  
2018 ◽  
Vol 91 (3) ◽  
pp. 230-232
Author(s):  
Leszek Bielenda ◽  
Wojciech Obrocki ◽  
Maciej Masłyk ◽  
Jan Sieniawski
Keyword(s):  
Fatigue Test ◽  
Eddy Current ◽  
Vibration Amplitude ◽  
Aircraft Engine ◽  
Fatigue Tests ◽  
Compressor Blade ◽  
Additional Test ◽  
Blade Vibration ◽  
Comparison Research ◽  
Engine Compressor

Results of comparison research of various sensors types used in the fatigue tests for aircraft engine compressor blade vibration amplitude measurement were analysed. Sensors under tests: inductive, capacitive, eddy-current, laser and vibration. Presented were sensors characteristics and their faults. Additional test stand instrumentation was designed and performed, including mounting bracket.

scholarly journals Mistuning Effects on the Nonlinear Friction Saturation of Flutter Vibration Amplitude

2020 ◽  
Author(s):  
Carlos Martel ◽  
Salvador Rodríguez
Keyword(s):  
Vibration Amplitude ◽  
Gas Flow ◽  
Travelling Waves ◽  
Computational Cost ◽  
Travelling Wave ◽  
Nonlinear Friction ◽  
Blade Vibration ◽  
Bladed Disk ◽  
Spring System ◽  
Mass Spring

Abstract The blade vibration level of an aerodynamically unstable rotor is a quantity of crucial importance to correctly estimate the blade fatigue life. This amplitude is the result of the balance between the energy pumped into the blades by the gas flow, and the nonlinear dissipation at the blade-disk contact interfaces. In a tuned configuration, the blade displacements can be described as a travelling wave consisting of one fundamental nodal diameter and frequency and its higher harmonics, and the problem can be reduced to the computation of a time periodic solution in just one sector. This simplification is no longer valid for a mistuned bladed disk. The resulting nonlinear vibration of the mistuned system is a combination of several travelling waves with different number of nodal diameters, coupled through mistuning. In this case, the complete bladed disk has to be considered, which requires an extremely high computational cost, and, for this reason, reduced order models (ROM) are required to analyze this situation. In this work, we use a 3 DOF/sector mass-spring system to describe the nonlinear friction saturation of the flutter vibration amplitude of a realistic mistuned bladed disk. The convergence of the solution of the mass-spring system is still quite slow because of the presence of many unstable modes with very similar growth rates. In order to speed-up the simulations a simpler asymptotic ROM is derived from the mass-spring model, which allows for much faster integration times. The simulations of the asymptotic ROM are compared with the measurements obtained in the European project FUTURE, where an aerodynamically unstable LPT rotor was tested with different intentional mistuning patterns.

On-line Monitoring of Gas Turbines to Improve Their Availability, Reliability, and Performance Using Both Process and Vibration Data

2012 ◽  
pp. 334-343 ◽  
Author(s):  
Osama Ashour ◽  
Abdurrahman Khalidi ◽  
Ever Fadlun ◽  
Nicola Giannini ◽  
Marco Pieri ◽  
...  
Keyword(s):  
Gas Turbines ◽  
Vibration Data ◽  
On Line ◽  
And Performance

Frequency Distribution of Blades in Turboengines and Vibration Characteristics of Mistuned Blades

1985 ◽  
Author(s):  
Ming-Fu Liao ◽  
Da-Kuan Shen
Keyword(s):  
Probability Distribution ◽  
Frequency Distribution ◽  
Gaussian Distribution ◽  
Vibration Amplitude ◽  
Vibration Characteristics ◽  
Frequency Difference ◽  
Blade Vibration ◽  
One Stage

In this paper, the probability distribution of blade frequencies is given as a Gaussian distribution approximately. The computations for comparing and simulating the effects of blade mistune on blade-disk vibration are made, which show that in general cases, blade mistune will cause the blade vibration amplitude to increase 20–30%. If the frequency difference of the blades on one stage is within ± 2%, the effect of mistune on the blade vibration will not be obvious. It is suggested that the blades can be divided into groups for mounting them and the frequency difference in each group not exceeds a certain range, for example, ± 2%.

Recent Blade Vibration Techniques

1967 ◽  
Vol 89 (3) ◽  
pp. 437-444 ◽  
Author(s):  
E. K. Armstrong
Keyword(s):  
Service Life ◽  
Fatigue Properties ◽  
Compressor Blades ◽  
Blade Vibration ◽  
Jet Engine ◽  
Vibration Data ◽  
Intake Flow

The methods which have been used recently to predict the amplitudes of vibration of compressor blades are explained. Examples for resonances with maldistributions in the intake flow and downstream blockages are given. Two techniques of obtaining blade vibration data from the HP shaft of a two-shaft jet engine are described. By comparing the measured amplitudes with the fatigue properties of blading, a parameter has been established which is used in assessing the seriousness of a vibration when considering its service life.

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