Washio Recent Developments in Cavitation Mechanisms

A Guide for Scientists and Engineers
1. Auflage 2014
ISBN: 978-1-78242-176-4
Verlag: Elsevier Science & Techn.
Format: EPUB
Kopierschutz: Adobe DRM (»Systemvoraussetzungen)

E-Book, Englisch, 288 Seiten

How does cavitation start? Presently, the nucleus theory provides the answer to this fundamental question. However the idea of nuclei contains inaccuracies that cannot be rationalized. Recent Developments in Cavitation Mechanisms discusses the uncertainties surrounding the nucleus theory, and proposes another theory of cavitation mechanism. Characteristically, the new theory is based on recent discoveries of cavity generation phenomena in separating flows. This book consists of chapters that introduce topics such as unsoundness of cavitation nuclei, and phenomena of cavity generation on walls of flow separation in hydraulic oil and water flows. Subsequent chapters cover the mechanism of cavity generation at point of flow separation, nucleation by contact motion between solids in liquid and a proposal of new cavitation mechanism based on flow separation and solid contact. The final chapters present the demonstration of a new mechanism in the hydraulic poppet valve and a concluding summary. - proposes a new mechanism of cavitation inception in liquid machines - describes in detail phenomena of cavity generation at point of flow separation recently discovered by the author - discusses peculiar properties of flow separation as cause of cavity generation - presents abundant experimental data of incipient cavitation obtained with high resolution of time and space - provides supplementary materials of slow motion videos that can help understand the very rapid and minute phenomena of cavity generation which has been discovered by the author and will be still unfamiliar to many

Seichi Washio is an emeritus professor of Okayama University, Okayama, Japan.

Autoren/Hrsg.

Washio, Seiichi

Inhaltsverzeichnis

1;Cover
;1
2;Recent developments in cavitation mechanisms: A guide for scientists and engineers
;4
3;Copyright
;5
4;Contents;6
5;List of figures and tables
;10
5.1;Figures;10
5.2;Tables;23
6;Preface;24
7;Acknowledgements;28
8;About the author;30
9;1 Review of cavitation nuclei
;32
9.1;1.1 Traditional pictures of nuclei;32
9.2;1.2 Nuclei in hydraulic mineral oil;34
9.3;1.3 Unsoundness of traditional nuclei models;53
9.4;1.4 Tribonucleation;60
9.5;1.5 Appendix I: Saturated solubility, diffusion coefficient and surface tension
;61
9.6;1.6 Appendix II: Effects of bubble on transient wave;72
9.7;1.7 References;73
10;2 Experimental methods
;76
10.1;2.1 Preliminary remarks;76
10.2;2.2 Microscope;77
10.3;2.3 Photography;78
10.4;2.4 Laser beam transmission;79
10.5;2.5 Measurements of physical quantities;80
10.6;2.6 Flows and channels;81
10.7;2.7 Observation of tribonucleation;82
10.8;2.8 References;82
11;3 Cavitation inception in separating oil flows
;84
11.1;3.1 Test channels for observation of cavitation;84
11.2;3.2 Experimental parameters;88
11.3;3.3 Oil flows with separation and reattachment in two-dimensional constriction
;89
11.4;3.4 Oil flows separating at a tip of needle projection
;119
11.5;3.5 Oil flows separating from smooth surface
;135
11.6;3.6 Summary;160
11.7;3.7 References;161
12;4 Cavitation inception in separating water flows
;164
12.1;4.1 Experimental apparatus;164
12.2;4.2 Cavity generation and cavitation in separating water flows
;167
12.3;4.3 Pressure dependence of cavity generation;178
12.4;4.4 Choking of water fl ow in 2-D constriction;181
12.5;4.5 Summary;187
12.6;4.6 References;188
13;5 Singular properties of flow separation as a cause of cavitation inception
;190
13.1;5.1 Tensions at point of flow separation
;190
13.2;5.2 Heat generation at point of separation;198
13.3;5.3 PIV inspection of separation flow
;202
13.4;5.4 Mechanism of tension and heat generations by flow separation
;206
13.5;5.5 Hypothesis of cavity generation mechanism at point of flow separation
;210
13.6;5.6 References;213
14;6 Tribonucleation by contact motion between solids in liquid
;216
14.1;6.1 Tribonucleation;216
14.2;6.2 Nucleation by separation of solid walls in liquid;218
14.3;6.3 Nucleation by sliding motion between surfaces contacting in liquid;235
14.4;6.4 Summary;245
14.5;6.5 References;246
15;7 Cavity generation by flow separation and solid contact in a hydraulic poppet valve
;248
15.1;7.1 Preliminary remarks;248
15.2;7.2 Experimental setup;249
15.3;7.3 Cavitation in a poppet valve with fixed clearance
;254
15.4;7.4 Cavitation in a poppet valve with variable clearance;268
15.5;7.5 Summary;280
15.6;7.6 Reference;281
16;Afterword;282
17;Index;284