Cativation of hydraulic machinery

Cavitatio n o f

Hydrauli c Machiner y

HYDRAULI C MACHINER Y BOO K SERIES

- Hydraulic Design of Hydraulic Machinery

Editor: Prof H Radha Krishna

- Mechanical Design and Manuíacturing of Hydraulic

Machinery

Editor: ProỊ Mei z Y

- Transỉent Phenomena of Hydraulic Machinery

Editors: Prof s Pejovic, Dr A p Boldy

- Cavitation of Hydraulic Machinery

Editor: Proị Li s c

- Erosion and Corrosion of Hydraulic Machinery

Editors: ProỊ Duan c G, ProỊ V Karelin

- Vibration and Oscillation of Hydraulic Machinery

Editor: PTOỊ H Ohashi

- Control of Hydraulic Machinery

Editor: ProỊ H Brekke

The International Editorial Committee (IECBSHM):

Chairman: ProỊ Duan c G

Treasurer: Dr R K Turton

Committee Members:

ProỊ H Brekke (Norway)

ProỊ E Egusquiza (Spain)

Dr H R Graze (Australia)

ProỊ p Henry (Switzerland).

ProỊ V Kareíin (USS)

ProỊ Li Sheng-cai (China)

ProỊ M Tadeu de Almeida (Brazil)

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ProỊ Ả Mobarak (Egypt)

ProỊ H Netsch (Canada)

Prof s Peịovic (Yugoslavia)

ProỊ H Petermann (Germany)

ProỊ c s Song (USA)

ProỊ Hans Ingo Weber (Brazil)

Honorary Members:

Prof B Chaiz (Switzerland)

Secretary: ProỊ Li s c

DĩÁP Boldy

Proị V p Chebaevski (USS)

ProỊ M Fanelli (Italy)

ProỊ R Guarga (Uruguay)

Dr H B Horlacher (Germany)

ProỊ G Krịvchenko (USS)

ProỊ Liu ỏ K (China)

PTOỊ c s Marùn (USA)

ProỊ Mei Zu-yan (China)

ProỊ H Murai (Japan)

ProỊ H Ohashi (Japan)

ProỊ D Perez-Franco (Cuba)

ProỊ H c Radha Krishna (India)

ProỊ c Thirriot (Prance)

ProỊ G Ziegler (Austria)

PTOỊ J Raabe (Germany)

^ ị p SERIES ÔN HYDRAULIC MACHINERY - VOL.1

Committee Chairman: c. G. Duan Series Editor: s. c. Li

Cavitation of

Hydraulic Machinery

Edito r

s. c. Li

University oi Warwick, U.K.

Imperial College Press

Published by

Imperial College Press

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London WC2H 9HE

Distributed by

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CAVITATION OF HYDRAULIC MACHINERY

Copyright © 2000 by Imperial College Press

AU rìghts reserved. This book, ÓT parts thereo/. may noi be reproduced in anyform or hy any means.

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ISBN 1-86094-257-1

Printed in Singapore by Ưto-Print

CONTENTS

References

3 Bubble Dynamics

Part 1: Single Bubble

A Shima

3.1 Rayleigh Analysis

3.1.1 Besant's Problem

xui

XV

xix

Ì

Preface

Foreword of the Editor

Contributing Authors

Ì Introduction

s c Li

1.1 Cavitation Ị

1.1.1 Discovery

1.1.2 ClassiScation

1.2 Hydraulic Machinery and Cavitation

3

1.2.1 Problems Caused by Cavitation

3

1.2.2 Combating Cavitation

Reíerences

2 Cavitation and Cavitation Types

A J Acosta

2.1 Cavitation Phenomenon

2.1.1 Cavitation

2.1.2 Hydrodynamic Cavitation

2.2 Types oi Cavitation

2.2.1 Cavitation Index

2.2.2 Scale ESects and Cavitation Types 12

2.3 Cavitation Eữects

2.3.1 General Phenomena

2.3.2 InAuences ôn Machine Períormance 25

2.3.3 System Stability

2.4 Cavitation Nucleation and Inception

2.4.1 Inception

2.4.2 Nuclei Measurement

2.4.3 Concluding Remarks

3 8

40

5

24

24

28

30

30

47

47

47

47

V

vi Contents

3.1.2 Rayleigh's Solution 48

3.2 Vaporous and Gaseous Bubbles 49

3.2.1 Classiíìcation 49

3.2.2 Stability 49

3.3 Viscosity and Compressibility Eíĩects 50

3.3.1 Eíĩects of Viscosity and Suríace Tension 50

3.3.2 Compressibility Eữect 50

3.4 Bubble Rebound 53

3.4.1 Introduction 53

3.4.2 Studies of Rebound 53

3.5 Nonspherical Collapse and Micro-jet Formation 54

3.5*1 Collapse near Solid Wall 54

3.5.2 Collapse in Contact with Solid Wall 55

3.6 Pressures Generated át Collapse 57

3.6.1 Impact Pressure and Their Modes 57

3.6.2 Temperature Effect 60

Reíerences 61

Part 2: Multi-Bubbles (stochastic Behaviour) 65

s c Li

3.7 Origins oi Bubble Stochasticity 65

3.7.1 Introduction 65

3.7.2 Bubble-Boundary Interaction 67

3.7.3 Bubble-Bubble iioteraction 73

3.7.4 Bubble-Flow Field Interaction 94

3.7.5 Remarks 115

3.8 Stochastic Models oi Cavitation Bubbles 117

3.8.1 Introduction 117

3.8.2 Single-Event Model 117

3.8.3 Muĩti-Event (Cluster) Model 118

3.8.4 Comprehensive Model 120

3.9 Power Spectrum 121

3.9.1 Introduction 121

3.9.2 Spectrum of Single-Bubble Collapse 121

3.9.3 Spectrum for Sequence of Single Events 127

3.9.4 Spectrum for Sequence ofClusters 137

3.9.5 Spectrum for Comprehensive Sequence 148

Reíerences 153

157