An investigation of the relationship between acoustic emission, vibration, noise and cavitation structures on a Kaplan turbine
01 Sep 2007-Journal of Fluids Engineering-transactions of The Asme (American Society of Mechanical Engineers)-Vol. 129, Iss: 9, pp 1112-1122
TL;DR: In this paper, the authors investigated the relationship between different acoustic signals and visual appearance of cavitation and concluded that the cavitation itself is the source of the recorded signal, and proposed a semi-empirical model that links the visual appearance on the blade of the turbine to generated noise and vibration.
Abstract: The goal of the study was to explain the relationship between different acoustic signals and visual appearance of cavitation. Measurements of acoustic emission, vibration, and noise were performed on a Kaplan turbine model, with only two blades, in a cavitating condition. Since a model with only two blades was used, most of the side effects were eliminated, and it was concluded that the cavitation itself is the source of the recorded signal. Results showed an interesting relationship between the extent of the cavitation and the recorded data from sensors. At a decreasing cavitation number, the recorded amplitudes from all measurements first rose, experienced a local maximum, then fell to a local minimum, and finally rose again. The cavitation was also visually observed. It was concluded from the measurements that there are distinct correlations between acoustic emission, vibration, and noise on one side and the topology, extent, and type of cavitation structures on the other side. A physical explanation for the phenomenon was introduced and included in a semi-empirical model that links the visual appearance of cavitation on the blade of the turbine to the generated noise and vibration.
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TL;DR: The meeting of the Advisory Technical Committees of the International Electrotechnical Commission (ITC) was held in Brussels from March 27th to April 1st, 1989 as mentioned in this paper.
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01 Oct 2013TL;DR: In this paper, the fundamental physical processes involved in bubble dynamics and the phenomenon of cavitation are described and explained, and a review of the free streamline methods used to treat separated cavity flows with large attached cavities is provided.
Abstract: This book describes and explains the fundamental physical processes involved in bubble dynamics and the phenomenon of cavitation. It is intended as a combination of a reference book for those scientists and engineers who work with cavitation or bubble dynamics and as a monograph for advanced students interested in some of the basic problems associated with this category of multiphase flows. A basic knowledge of fluid flow and heat transfer is assumed but otherwise the analytical methods presented are developed from basic principles.
The book begins with a chapter on nucleation and describes both the theory and observations of nucleation in flowing and non-flowing systems. The following three chapters provide a systematic treatment of the dynamics of the growth, collapse or oscillation of individual bubbles in otherwise quiescent liquids. Chapter 4 summarizes the state of knowledge of the motion of bubbles in liquids. Chapter 5 describes some of the phenomena which occur in homogeneous bubbly flows with particular emphasis on cloud cavitation and this is followed by a chapter summarizing some of the experiemntal observations of cavitating flows. The last chapter provides a review of the free streamline methods used to treat separated cavity flows with large attached cavities.
2,994 citations
TL;DR: In this paper, a study of visual and erosion effects of cavitation on simple single hydrofoil configurations in a cavitation tunnel was made, where a thin copper foil was used as an erosion sensor.
207 citations
TL;DR: The meeting of the Advisory Technical Committees of the International Electrotechnical Commission (ITC) was held in Brussels from March 27th to April 1st, 1989 as mentioned in this paper.
Abstract: Meetings of the Advisory Technical Committees of the International Electrotechnical Commission were held in Brussels March 27th to April 1st. The meetings were attended by delegates from eight national committees — Belgium, France, Great Britain, Holland, Italy, Spain, Switzerland, and the United States. There were about 40 delegates in all.
177 citations
TL;DR: In this article, a study of visual and erosion effects of cavitation on simple single hydrofoil configurations in a cavitation tunnel was made, where a thin copper foil, applied to the surface of the hydrofoils, was used as an erosion sensor.
175 citations
TL;DR: In this article, the phase distribution within gas and liquid two-phase flows is characterized using local probes, where two sensors placed in series enable void fraction, velocity, and chord length measurements.
Abstract: A current method used to characterize the phase distribution within gas (or vapor)/liquid two-phase flows consists of using local probes. Two sensors placed in series enable void fraction, velocity, and chord length measurements. The choice of the data treatment method depends strongly on the unsteady behavior of the flow: the higher the velocity fluctuations, the more complex and time consuming the data treatments. Three different methods have been developed to study various cavitating flow conditions. They have been applied to characterize two-phase flows within sheet cavities using a double optical probe.
119 citations