Cavitation Noise

2021 ◽  
pp. 177-210
Author(s):  
Yves Lecoffre ◽  
M.M. Oberai ◽  
V.H. Arakeri
Keyword(s):  
Cavitation Noise

Assessment of Noise Signature for a Cavitating Centrifugal Pump

2021 ◽  
pp. 1-25
Author(s):  
Christopher Stephen ◽  
Dhanasekaran Arumugam ◽  
Kumaraswamy Sivasailam
Keyword(s):  
Centrifugal Pump ◽  
Flow Rate ◽  
Mobile Application ◽  
Cavitation Noise ◽  
Normal Operating Condition ◽  
Operating Condition ◽  
Low Specific Speed ◽  
Current Operating Condition ◽  
Noise Signature ◽  
Current Operating

Abstract In recent days, sophisticated instruments have emerged to obtain an online measurement of performance parameters from centrifugal pump of different kinds and the signals can be directed to the hands of pump user through mobile application. With this in mind, a centrifugal pump of low specific speed was chosen for cavitation studies from 80% to 120% of nominal flow rate and for three different speeds. An assessment was carried out for cavitation noise signature from those operating condition of that pump. The result of cavitation noise based on peak magnitude as well as average revealed a nature in relation to cavitation coefficient and it greatly depends on the flow rate with respect to nominal flow rate. The noise envelope for the flow rate at best efficiency and above was having similar trend whereas at flows less than the nominal, it was totally different. So the criteria for finding the deviation in noise cannot be uniform for all flow rates. In this paper, the method adapted was to impose a trend line to the measured cavitation noise information and to find out the deviation with respect to normal operating condition. It was concluded that detection of abnormality in pumps due to cavitation effects requires the current operating condition to be diagnosed first and then proper criteria for deviation in noise has to be imposed.

Cavitation Noise Spectra Prediction with Hybrid Models

2019 ◽  
pp. 152-157
Author(s):  
Francesca Cipollini ◽  
Fabiana Miglianti ◽  
Luca Oneto ◽  
Giorgio Tani ◽  
Michele Viviani ◽  
...  
Keyword(s):  
Hybrid Models ◽  
Cavitation Noise ◽  
Noise Spectra

Transcritical Patterns of Cavitating Flow and Trends of Acoustic Level

2001 ◽  
Vol 123 (4) ◽  
pp. 850-856 ◽  
Author(s):  
Wei Gu ◽  
Yousheng He ◽  
Tianqun Hu
Keyword(s):  
Liquid Flow ◽  
High Speed ◽  
Cavity Flow ◽  
Periodic Flow ◽  
Cavitating Flows ◽  
Cavitation Noise ◽  
Cloud Cavitation ◽  
Three Stages ◽  
Cavity Shedding ◽  
Axisymmetric Bodies

Hydroacoustics of the transcritical cavitating flows on a NACA16012 hydrofoil at a 2/5/8-degree angle of attack and axisymmetric bodies with hemispherical and 45-degree conical headforms were studied, and the process of cloud cavitation shedding was observed by means of high-speed cinegraphy. By expressing the cavitation noise with partial acoustic level, it is found that the development of cavitation noise varies correspondingly with cavitation patterns. The instability of cavitation is a result of cavity-flow interaction, and is mainly affected by the liquid flow rather than by the cavitation bubbles. A periodic flow structure with a large cavitation vortex is observed and found to be responsible for inducing the reentrant-jet and consequent cavitation shedding, and explains the mechanism of periodic cavitation shedding from a new viewpoint. New terms for the three stages, growing, hatching and breaking, are used to describe the process of cavity shedding.

Paper 14: Acoustic Detection of Cavitation

1966 ◽  
Vol 181 (1) ◽  
pp. 1-8 ◽  
Author(s):  
I. S. Pearsall
Keyword(s):  
High Frequency ◽  
Critical Frequency ◽  
Low Frequency ◽  
Francis Turbine ◽  
Frequency Noise ◽  
Performance Tests ◽  
Acoustic Detection ◽  
Cavitation Noise ◽  
Further Development ◽  
Onset Of Cavitation

The onset of cavitation in a hydraulic machine can be determined visually and its effect on performance by performance tests. It would be convenient to have an alternative method that required neither transparent sections nor expensive tests. Initial tests have been made measuring noise over a frequency range of 20 c/s-20 kc/s in one-third octave bands, on a number of pumps and turbines. An accelerometer attached to the casing was used. The tests indicated that, generally, the onset of cavitation was accompanied by a rise in the high-frequency noise, whilst the low-frequency noise increased as the cavitation developed. A maximum of cavitation noise was reached before the efficiency and load fell off. In some cases difficulty was experienced because blade cavitation was drowned by noise caused by other cavitation, such as the vortex in a Francis turbine. It also appears that the noise following the onset of cavitation is at the frequency which is used as a critical frequency in accelerated erosion tests. Further development of techniques is required, but the initial tests are encouraging.

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