Δημοσιεύσεις ΕΘΣ/ΕΜΠ: Μέθοδοι Διαγνωστικής Αεριοστροβίλων με τη χρήση κραδασμών ή άλλων μέτρων ταχείας απόκρισης (ήχος, δυναμική πίεση κ.α.)
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Aretakis N., Mathioudakis K., Kefalakis M., Papailiou K.D., “Turbocharger Unstable Operation Diagnosis Using Vibroacoustic Measurements”, ASME Journal of Engineering for Gas Turbines and Power, Vol 126, No. 3, October 2004, pp. 840-847 [abstract] [PDF presentation] (also: ASME paper GT2003-38321)
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Aretakis N., Mathioudakis K., Dedoussis V., "Derivation of Signatures for Faults in Gas Turbine Compressor Blading", Control Engineering Practice, Vol. 6, No. 8, August 1998, pp. 969-974 [abstract] (also: IFAC symposium on fault detection, supervision and safety for technical processes, SAFEPROCESS'97, Aug. 26-28, 1997, Kingston Upon Hall, UK)
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Stamatis A., Aretakis N., Mathioudakis K., "Blade Fault Recognition Based on Signal Processing and Adaptive Fluid Dynamic Modelling", ASME Journal of Engineering for Gas Turbine and Power, Vol. 120, No. 3, July 1998, pp 543-549 [abstract] [PDF presentation] (also ASME paper 97-GT-197)
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Aretakis N., Mathioudakis K., "Wavelet Analysis for Gas Turbine Fault Diagnostics", ASME Journal of Engineering for Gas Turbine and Power, Vol. 119, No. 4, , October 1997, pp. 870-876 [abstract] (also: ASME paper 96-GT-343)
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Aretakis N., Mathioudakis K., "Radial Compressor Fault Identification using Dynamic Measurement Data", ASME paper 96-GT-102, 41st ASME International Gas Turbine and Aeroengine Congress and Exposition, June 1996, Birmingham, UK [abstract] [PDF presentation]
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Baligand B., Garnier B., Mathioudakis K., Smith M.K., "Gas Turbine Health Monitoring Demonstrator", 2nd International Conference on Acoustical and Vibratory Surveillance Methods and Diagnostic Techniques - SFM/IMEKO/SFA - SEMLIS, 10-12 Oct 1995, pp. 521-531
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Mathioudakis K.: “Diagnostic Techniques Based on Fast Response Measurements”, in 'Measurement Techniques', VKI Lectures Series 1995-2, Measurement Techniques
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Dedoussis V., Mathioudakis K., Papailiou K.D., "Numerical Simulation of Blades Fault Signatures from Unsteady Wall Pressure Signals", ASME paper 94-GT-289, 39th ASME International Gas Turbine and Aeroengine Congress and Exposition, June 1994, Hague, Netherlands. Accepted for publication in Journal of Engineering for Gas Turbine and Power, ASME.
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Loukis E., Wetta P., Mathioudakis K., Papathanasiou A., Papailiou K.D., "Combination of Different Unsteady Quality Measurements for Gas Turbine Blade Fault Diagnosis", ASME Paper 91-GT-201, 36th ASME International Gas Turbine and Aeroengine Congress, June 3-6, 1991, Orlando, Florida, USA. (Best paper award, of the Controls and Diagnostics Committee of ASME)
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Mathioudakis K., Papathanasiou A.,Loukis E., Papailiou K.D., "Fast Response Wall Pressure Measurement as a Means of Gas Turbine Blade Fault Identification". ASME Journal of Engineering for Gas Turbines and Power, Vol. 113, No. 2, April 1991, pp. 269-275
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Mathioudakis K., Loukis E., Papailiou K.D., "Casing Vibration and Gas Turbine Operating Conditions", ASME Journal of Engineering for Gas Turbine and Power, Vol. 112, No 4, Oct. 1990, pp. 478-485. (also: ASME Paper 89-GT-78)
Αρχή Σελίδας
Turbocharger Unstable Operation Diagnosis Using Vibroacoustic Measurements
Authors:Aretakis N., Mathioudakis K., Kefalakis M., Papailiou K.D.
Abstract
The possibility to detect unstable operating condition (stall or surge) of an automotive turbocharger using vibration or acoustic measurements is studied. An experimental study is performed, in order to acquire and analyze test data, to find out whether vibration or acoustic measurements can be correlated to aerothermodynamic operating condition. An instrumentation set allowing the definition of the operating point on the map of the compressor of the turbocharger is used. Hot wires the compressor inlet serve as flow condition indicators and provide a clear indicator of the presence or not of instabilities, such as rotating stall or surge. Accelerometers are mounted on the casing and microphones are placed in the vicinity of the compressor casing, to measure vibration and sound emission. Data covering an extensive range of the compressor performance map have been collected and analyzed. Signal features from the different measuring instruments are discussed. Using such features, a bi-parametric criterion is established for determination of whether the compressor operates in the stable part of its performance characteristic or in the presence of unstable operation phenomena (rotating stall, surge). The possibility of generalizing the validity of observations is supported, by presenting results from testing a second turbocharger, which is shown to exhibit similar behavior
Derivation of Signatures for Faults in Gas Turbine Compressor Blading
Authors:Aretakis N., Mathioudakis K., Dedoussis V.
Abstract
A procedure for the derivation of signatures for faults in the blades of a gas turbine is presented here. A variety of blade faults,corresponding to changes in the angle or spacing of one or more blades, are examined. A ?uid dynamic simulation model is used to derive the unsteady pressure signals sensed by a stationary transducer for the cases of faulty blades. The blade fault signatures are derived by processing these signals using Fourier techniques. The features of blade fault signatures are studied. Finally, the possibilities they o§er for the discrimination and identi?cation of di§erent possible blade faults are also examined.
Blade Fault Recognition Based on Signal Processing and Adaptive Fluid Dynamic Modelling
Authors:Stamatis A., Aretakis N., Mathioudakis K.
Abstract
An approach for identification of faults in blades of a gas turbine, based on physical modelling is presented. A measured quantity is used as an input and the deformed blading configuration is produced as an output. This is achieved without using any kind of "signature", as is customary in diagnostic procedures for this kind of faults. A fluid dynamic model is used in a manner similar to what is known as "inverse design methods": the solid boundaries that produce a certain flow field are calculated by prescribing this flow field. In the present case a signal, corresponding to the pressure variation on the blade-to-blade plane, is measured. The blade cascade geometry that has produced this signal is then produced by the method. In the paper the method is described and applications to test cases are presented. The test cases include theoretically produced faults as well as experimental cases, where actual measurement data are shown to produce the geometrical deformations that existed in the test engine
Wavelet Analysis for Gas Turbine Fault Diagnostics
Authors:Aretakis N., Mathioudakis K.
Abstract
The application of wavelet analysis to diagnosing faults in gas turbines is examined in the present paper. Applying the wavelet transform to time signals obtained from sensors placed on an engine gives information in correspondence to their Fourier transform. Diagnostic techniques based on Fourier analysis of signals can therefore be transposed to the wavelet analysis. In the paper the basic properties of wavelets,in relation to the nature of turbomachinery signals, are discussed. The possibilities for extracting diagnostic information by means of wavelets are examined, by studying the applicability to existing data from vibration, unsteady pressure, and acoustic measurements. Advantages offered, with respect to existing methods based on harmonic analysis, are discussed as well as particular requirements related to practical application.
Radial Compressor Fault Identification using Dynamic Measurement Data
Authors:Aretakis N., Mathioudakis K.
Abstract
The exploitation of different unsteady quantity measurements for identifying mechanical alterations on a radial compressor with a vaned diffuser is examined in this paper. Measurements of sound emission, casing vibration and unsteady inner wall pressure are performed. The mechanical alterations considered have been chosen in order to reproduce or simulate faults in the compressor. They include the insertion of an inlet obstruction, an obstruction in a diffuser passage, variation of impeller tip clearance, and impeller fouling. Processing these measurement data leads to the derivation of fault signatures which can be utilized for identifying them. The suitability of measuring each of the above physical quantities is discussed with respect to their sensitivity to particular faults. The dependence of the fault signatures on operating point is also examined. It's demonstrated that minor faults which do not affect compressor operation and are not detectable by performance monitoring, can possibly be detected by the proposed methodology.