The application of acoustic emission for detecting incipient cavitation and the best efficiency point of a 60kW centrifugal pump: case study

Alfayez, L.; Mba, David; Dyson, G.

doi:10.1016/j.ndteint.2004.10.002

Cited by 95 publications

(42 citation statements)

References 11 publications

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“…Cavitation in air corresponds to a continuous broadband spectrum (20 Hz -20 kHz) [25], and incipient cavitation produced an increase in rms and peak amplitude [14], [25]. Similar results underwater were found whilst studying a similar frequency range (0 -100 kHz) [25].…”

Section: Renewablessupporting

confidence: 57%

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Acoustic emission health monitoring of marine renewables: Illustration with a wave energy converter in Falmouth Bay (UK)

Walsh

Bashir

Thies

et al. 2015

OCEANS 2015 - Genova

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Abstract-Marine renewable energy (MRE) is an emerging technology and at present there are an increasing number of MRE prototypes and full-scale devices deployed. The future commercialization in the near future may contribute to the mitigation of carbon emissions and diversify the renewable electricity generation portfolio. Because of the high costs of marine intervention, it is important to establish reliable, remote monitoring techniques. The underwater sound around MRE devices is often monitored for environmental impact assessments. This approach can also be potentially utilized to monitor the engineering health of MRE devices. This is the objective of the project AEMORE (Acoustic Emission technology for environmental and engineering health Monitoring of Offshore Renewable Energy), jointly conducted by the Universities of Exeter and Bath, with J+S Ltd. Acoustic Emission (AE) monitoring is already used for Structural Health Monitoring (SHM) of land-based structures and devices such as wind turbines. AE allows faults and defects to be detected early in a device's lifetime, providing more time to plan and implement necessary maintenance and repair procedures to avoid catastrophic failure. This is highly desirable for MRE structures, which operate in energetic seas with tight weather access windows. This paper explores the remit for AE monitoring to SHM and maintenance planning for MRE devices and demonstrates that this novel application is principally feasible. A brief review of the state of the art of AE for land-based systems aids to illustrate how its techniques can be applied to underwater environments and MRE components. This literature review will inform a classification system that relates likely failure modes to their expected acoustic emissions. The results from previous underwater environmental studies are used to evaluate their potential for SHM of MRE structures. AE environmental data collected during the operation of the Fred Olsen Lifesaver wave energy converter at the Falmouth Bay Test site (FaBTest, SW UK) is used to demonstrate this novel application. The case study provides proof that this concept is valid for underwater SHM of marine renewable structures.

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Section: Renewablessupporting

confidence: 57%

“…For the operation of pump machinery, it is accepted that best efficiency occurs with minimal flow turbulence in the system, i.e. minimum AE activity [14]. For composite materials such as in moorings, there are direct correlations between AE and breaks of fibers [15] or steel wire cables [16].…”

Section: B Acoustic Emission Monitoringmentioning

confidence: 99%

Acoustic emission health monitoring of marine renewables: Illustration with a wave energy converter in Falmouth Bay (UK)

Walsh

Bashir

Thies

et al. 2015

OCEANS 2015 - Genova

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show abstract

“…Traditionally, there have been efforts to detect cavitation using vibration, pressure, acoustic emission or sound measurements. A variety of studies concentrate on the cavitation of pumps, see [Čudina, 2003], [Alfayez et al, 2005] and [Al-Hashmi et al, 2005]. Cavitation is extremely harmful to turbines, as it damages the surfaces of runners and flow channels, e.g.…”

Section: Introductionmentioning

confidence: 99%

Vibration Analysis of Cavitation in Kaplan Water Turbines

Lahdelma

Juuso

2008

IFAC Proceedings Volumes

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Cavitation is harmful to water turbines and may cause operation delays of several weeks. The real-time detection of cavitation risk is increasingly important, and even narrow cavitation-free power ranges can be utilised in load optimisation. Higher derivative signals x (3) and x (4) calculated from acceleration signals are very suitable for detecting impacts. This paper introduces a generalised moment τ σ M p α which is defined by three parameters: the sensitivity of the moment improves when the order p of the moment increases, especially when short sample time τ is used. In this study, sufficently good results were obtained with moments where the order of derivation α =4 ,p ≈ 4, and τ =3s. These moments detect the normal operating conditions, which are free of cavitation, and also provide a clear indication for cavitation risk at an early stage. Sufficiently long signals are required for producing reliable maximum moments and data for analysing short-term cavitation. On-line cavitation monitoring is feasible with this approach since the analysis does not need high frequency ranges and the sample times are very short. The moment can be analysed first, and it is then possible to obtain the cavitation index if the moment value exceeds the threshold. Data compression is very efficient as the detailed analysis only requires the feature values of the appropriate samples.

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“…Cavitation noise were also observed in acoustically driven mineral insulating oil filled vessel [13].…”

Section: Introductionmentioning

confidence: 79%

Acoustic Spectra of Ultrasound Induced Cavitations in Insulating Oils

et al. 2008

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Acoustic emission measurement results of acoustically induced cavitation bubbles in insulating oil are presented in this paper. Spectral analysis of acquired by a broadband transducer acoustic emission signals is proposed as a diagnostic tool for estimation of aging properties of mineral insulating oils. The article describes the main parts of the designed and built measurement apparatus used for acoustic cavitation investigation in insulating oils. In this note representative results of the experimental data taken from the apparatus are shown.

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The application of acoustic emission for detecting incipient cavitation and the best efficiency point of a 60kW centrifugal pump: case study

Cited by 95 publications

References 11 publications

Acoustic emission health monitoring of marine renewables: Illustration with a wave energy converter in Falmouth Bay (UK)

Acoustic emission health monitoring of marine renewables: Illustration with a wave energy converter in Falmouth Bay (UK)

Vibration Analysis of Cavitation in Kaplan Water Turbines

Acoustic Spectra of Ultrasound Induced Cavitations in Insulating Oils

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