Exploration of a possibility to assess erosive cavitation by acoustic emission technique
Exploration of a possibility to assess erosive cavitation by acoustic emission technique
In order to complement the conventional model scale cavitation erosion test methods, research is being undertaken to explore the use of an acoustic emission technique to provide a quantified measure of cavitation. The amplitude of AE signals within a structure, such as a propeller shaft, is assumed to change in proportion with the pressure impact loads from the collapse of vapour cavities. Analysis of the power spectrum of the signals should show some meaningful parameters in relation to the cavitation intensity and frequency, which can be used as a quantitative index of the cavitation erosion risk. The main results of a preliminary study are provided with illustration of some results of the experiment using a G-32 type vibratory cavitation apparatus combined with a CFD simulation. It is found that the AE power spectrum indicated two main peak frequencies from the acoustic excitation and the sub-harmonic oscillation of the acoustic cavities as reported in the other relevant literature. However, the acoustic driving frequency component appeared much stronger and the sub-harmonic oscillation frequency appeared as a band rather than a single peak. An investigation on the vibration characteristics of the sonotrode revealed the vibration amplitude could vary in the order of about 15 % of that desired. This might partly explain the reason of the frequency band formation around a central frequency of the sub-harmonic oscillation. Further investigation on the possible causes is underway. It has still a long way to go to establish a new model test methodology, but it appears the AE signal amplitude response has a certain relation with the magnitude of cavitation impact loadings.
Keywords: cavitation
The American Society of Mechanical Engineers
Kim, Byoung Guk
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Fetherstonhough, Crispin
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Wilson, Philip
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Turnock, Stephen
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14 May 2018
Kim, Byoung Guk
6a0ffc7c-ca5d-440d-8a11-6d9eb9c1d4d7
Fetherstonhough, Crispin
b76c67b6-d1bb-4d44-8be3-69a2d6ec06d0
Wilson, Philip
8307fa11-5d5e-47f6-9961-9d43767afa00
Turnock, Stephen
d6442f5c-d9af-4fdb-8406-7c79a92b26ce
Kim, Byoung Guk, Fetherstonhough, Crispin, Wilson, Philip and Turnock, Stephen
(2018)
Exploration of a possibility to assess erosive cavitation by acoustic emission technique.
In Proceedings of the 10th International Symposium on Cavitation (CAV2018).
The American Society of Mechanical Engineers.
6 pp
.
Record type:
Conference or Workshop Item
(Paper)
Abstract
In order to complement the conventional model scale cavitation erosion test methods, research is being undertaken to explore the use of an acoustic emission technique to provide a quantified measure of cavitation. The amplitude of AE signals within a structure, such as a propeller shaft, is assumed to change in proportion with the pressure impact loads from the collapse of vapour cavities. Analysis of the power spectrum of the signals should show some meaningful parameters in relation to the cavitation intensity and frequency, which can be used as a quantitative index of the cavitation erosion risk. The main results of a preliminary study are provided with illustration of some results of the experiment using a G-32 type vibratory cavitation apparatus combined with a CFD simulation. It is found that the AE power spectrum indicated two main peak frequencies from the acoustic excitation and the sub-harmonic oscillation of the acoustic cavities as reported in the other relevant literature. However, the acoustic driving frequency component appeared much stronger and the sub-harmonic oscillation frequency appeared as a band rather than a single peak. An investigation on the vibration characteristics of the sonotrode revealed the vibration amplitude could vary in the order of about 15 % of that desired. This might partly explain the reason of the frequency band formation around a central frequency of the sub-harmonic oscillation. Further investigation on the possible causes is underway. It has still a long way to go to establish a new model test methodology, but it appears the AE signal amplitude response has a certain relation with the magnitude of cavitation impact loadings.
Keywords: cavitation
Text
cav2018-bgkim-final
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More information
Accepted/In Press date: 1 January 2018
e-pub ahead of print date: 14 May 2018
Published date: 14 May 2018
Venue - Dates:
10th International Symposium on Cavitation, Renaissance Baltimore Harborplace Hotel, Baltimore, United States, 2018-05-14 - 2018-05-16
Identifiers
Local EPrints ID: 421990
URI: http://eprints.soton.ac.uk/id/eprint/421990
PURE UUID: df32ebce-df4b-45e3-88a2-48d7dd27ff48
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Date deposited: 12 Jul 2018 16:30
Last modified: 16 Mar 2024 02:37
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Contributors
Author:
Byoung Guk Kim
Author:
Crispin Fetherstonhough
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