Brennen Christopher E. - Fundamentals of Multiphase Flows.pdf

(17557 KB) Pobierz
cabook.DVI
Fundamentals of
Multiphase Flows
Christopher E. Brennen
California Institute of Technology
Pasadena, California
Cambridge University Press 2005
ISBN 0521 848040
1
77370758.001.png
Preface
The subject of multiphase flows encompasses a vast field, a host of different
technological contexts, a wide spectrum of different scales, a broad range of
engineering disciplines and a multitude of different analytical approaches.
Not surprisingly, the number of books dealing with the subject is volumi-
nous. For the student or researcher in the field of multiphase flow this broad
spectrum presents a problem for the experimental or analytical methodolo-
gies that might be appropriate for his/her interests can be widely scattered
and dicult to find. The aim of the present text is to try to bring much
of this fundamental understanding together into one book and to present
a unifying approach to the fundamental ideas of multiphase flows. Conse-
quently the book summarizes those fundamental concepts with relevance to
a broad spectrum of multiphase flows. It does not pretend to present a com-
prehensive review of the details of any one multiphase flow or technological
context though reference to books providing such reviews is included where
appropriate. This book is targeted at graduate students and researchers at
the cutting edge of investigations into the fundamental nature of multiphase
flows; it is intended as a reference book for the basic methods used in the
treatment of multiphase flows.
I am deeply grateful to all my many friends and fellow researchers in the
field of multiphase flows whose ideas fill these pages. I am particularly in-
debted to my close colleagues, Allan Acosta, Ted Wu, Rolf Sabersky, Melany
Hunt, Tim Colonius and the late Milton Plesset, all of whom made my pro-
fessional life a real pleasure. This book grew out of many years of teaching
and research at the California Institute of Technology. It was my privilege to
have worked on multiphase flow problems with a group of marvelously tal-
ented students including Hojin Ahn, Robert Bernier, Abhijit Bhattacharyya,
David Braisted, Charles Campbell, Steven Ceccio, Luca d’Agostino, Fab-
rizio d’Auria, Mark Duttweiler, Ronald Franz, Douglas Hart, Steve Hostler,
2
Gustavo Joseph, Joseph Katz, Yan Kuhn de Chizelle, Sanjay Kumar, Harri
Kytomaa, Zhenhuan Liu, Beth McKenney, Sheung-Lip Ng, Tanh Nguyen,
Kiam Oey, James Pearce, Garrett Reisman, Y.-C. Wang, Carl Wassgren,
Roberto Zenit Camacho and Steve Hostler. To them I owe a special debt.
Also, to Cecilia Lin who devoted many selfless hours to the preparation of
the illustrations.
A substantial fraction of the introductory material in this book is taken
from my earlier book entitled “Cavitation and Bubble Dynamics” by
Christopher Earls Brennen, c
This book is dedicated with great affection and respect to my mother,
Muriel M. Brennen, whose love and encouragement have inspired me
throughout my life.
Christopher Earls Brennen
California Institute of Technology
December 2003.
3
1995 by Oxford University Press, Inc. It is
reproduced here by permission of Oxford University Press, Inc.
Contents
Preface page 2
Contents 10
Nomenclature 11
1INTRODUCTIONTOMU TIPHASEFLOW 9
1.1 INTRODUCTION
19
1.1.1 Scope
19
1.1.2 Multiphase flow models
20
1.1.3 Multiphase flow notation
22
1.1.4 Size distribution functions
25
1.2 EQUATIONS OF MOTION
27
1.2.1 Averaging
27
1.2.2 Conservation of mass
28
1.2.3 Number continuity equation
30
1.2.4 Fick’s law
31
1.2.5 Equation of motion
31
1.2.6 Disperse phase momentum equation
35
1.2.7 Comments on disperse phase interaction
36
1.2.8 Equations for conservation of energy
37
1.2.9 Heat transfer between separated phases
41
1.3 INTERACTION WITH TURBULENCE
42
1.3.1 Particles and turbulence
42
1.3.2 Effect on turbulence stability
46
1.4 COMMENTS ON THE EQUATIONS OF MOTION
47
1.4.1 Averaging
47
1.4.2 Averaging contributions to the mean motion
48
1.4.3 Averaging in pipe flows
50
1.4.4 Modeling with the combined phase equations
50
1.4.5 Mass, force and energy interaction terms
51
4
2 SINGLE PARTICLE MOTION 52
2.1 INTRODUCTION 52
2.2 FLOWS AROUND A SPHERE 53
2.2.1 At high Reynolds number 53
2.2.2 At low Reynolds number 56
2.2.3 Molecular effects 61
2.3 UNSTEADY EFFECTS 62
2.3.1 Unsteady particle motions 62
2.3.2 Effect of concentration on added mass 65
2.3.3 Unsteady potential flow 65
2.3.4 Unsteady Stokes flow 69
2.4 PARTICLE EQUATION OF MOTION 73
2.4.1 Equations of motion 73
2.4.2 Magnitude of relative motion 78
2.4.3 Effect of concentration on particle equation of motion 80
2.4.4 Effect of concentration on particle drag 81
3 BUBBLE OR DROPLET TRANSLATION 86
3.1 INTRODUCTION 86
3.2 DEFORMATION DUE TO TRANSLATION 86
3.2.1 Dimensional analysis 86
3.2.2 Bubble shapes and terminal velocities 88
3.3 MARANGONI EFFECTS 91
3.4 BJERKNES FORCES 95
3.5 GROWING BUBBLES 97
4 BUBBLE GROWTH AND COLLAPSE 100
4.1 INTRODUCTION 100
4.2 BUBBLE GROWTH AND COLLAPSE 100
4.2.1 Rayleigh-Plesset equation 100
4.2.2 Bubble contents 103
4.2.3 In the absence of thermal effects; bubble growth 106
4.2.4 In the absence of thermal effects; bubble collapse 109
4.2.5 Stability of vapor/gas bubbles
110
4.3 THERMAL EFFECTS
113
4.3.1 Thermal effects on growth
113
4.3.2 Thermally controlled growth
115
4.3.3 Cavitation and boiling
118
4.3.4 Bubble growth by mass diffusion
118
4.4 OSCILLATING BUBBLES
120
4.4.1 Bubble natural frequencies
120
5

Plik z chomika:

Inne pliki z tego folderu:

Inne foldery tego chomika:

Zgłoś jeśli naruszono regulamin