Application of sulfonimidoyl substituted allyltitanium (IV) complexes to the asymmetric synthesis of alkenyloxiranes, 2,3-dihydrofurans, tetrahydrofurans, unsaturated proline analogues and allylic alcohols [Elektronische Ressource] / vorgelegt von Surendra Babu Gadamsetty

Informations

• Publié par: rheinisch-westfalischen_technischen_hochschule_-rwth-_aachen
• Publié le: 01 janvier 2007
• Nombre de lectures: 33
• Poids de l'ouvrage: 2 Mo

Extrait

ON THE POTENTIAL OF LARGE EDDY
SIMULATION TO SIMULATE CYCLONE
SEPARATORS


Von der Fakultät für Maschinenbau der
Technischen Universität Chemnitz

Genehmigte

Dissertation

Zur Erlangung des akademischen Grades
Doktoringenieur
(Dr.-Ing.)
Vorgelegt
von M.Sc. Hemdan Hanafy Shalaby
geboren am 18.04.1967 in Ebehera, Ägypten


Gutachter:
Prof. Dr.-Ing. habil. Wozniak, Günter
Prof. Dr.-Ing. habil. Bernd Platzer
Prof. Dr.-Ing. habil. Dominique Thévenin





Chemnitz, den 24. Januar 2007


ON THE POTENTIAL OF LARGE EDDY
SIMULATION TO SIMULATE CYCLONE
SEPARATORS
By
M.Sc. Eng. Hemdan Hanafy Shalaby
SUBMITTED IN PARTIAL FULFILLMENT OF THE
REQUIREMENTS FOR THE DEGREE OF
DOCTOR OF ENGINEERING
AT
CHEMNITZ UNIVERSITY OF TECHNOLOGY
CHEMNITZ, GERMANY
JANUARY 2007
c Copyright by M.Sc. Eng. Hemdan Hanafy Shalaby, 2007CHEMNITZ UNIVERSITY OF TECHNOLOGY
DEPARTMENT OF
MECHANICS, CHAIR: FLUID MECHANICS
Theundersignedherebycertifythattheyhavereadandrecommend
to the Faculty of Mechanical Engineering for acceptance a thesis entitled
“On The Potential of Large Eddy Simulation to Simulate
Cyclone Separators” by M.Sc. Eng. Hemdan Hanafy Shalaby
in partial fulfillment of the requirements for the degree of
Doctor of Engineering.
Dated: January 2007
External Examiner:
Dominique Th´evenin
Research Supervisor:
Gun¨ ter Wozniak
Examining Committee:
Bernd Platzer
iiCHEMNITZ UNIVERSITY OF TECHNOLOGY
Date: January 2007
Author: M.Sc. Eng. Hemdan Hanafy Shalaby
Title: On The Potential of Large Eddy Simulation to
Simulate Cyclone Separators
Institute: Mechanics, Chair: Fluid Mechanics
Degree: Ph.D. Convocation: January Year: 2007
Permission is herewith granted to Chemnitz University of Technology
to circulate and to have copied for non-commercial purposes, at its discretion,
the above title upon the request of individuals or institutions.
Signature of Author
THE AUTHOR RESERVES OTHER PUBLICATION RIGHTS, AND
NEITHER THE THESIS NOR EXTENSIVE EXTRACTS FROM IT MAY
BE PRINTED OR OTHERWISE REPRODUCED WITHOUT THE AUTHOR’S
WRITTEN PERMISSION.
THE AUTHOR ATTESTS THAT PERMISSION HAS BEEN OBTAINED
FOR THE USE OF ANY COPYRIGHTED MATERIAL APPEARING IN THIS
THESIS (OTHER THAN BRIEF EXCERPTS REQUIRING ONLY PROPER
ACKNOWLEDGEMENTINSCHOLARLYWRITING)ANDTHATALLSUCHUSE
IS CLEARLY ACKNOWLEDGED.
iiiTo my parents, my wife, and my children.
ivTable of Contents
Table of Contents v
List of Tables vii
Abstract xiv
Acknowledgements xvi
1 Introduction and Literature survey 1
1.1 Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Literature survey . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.3 Thesis goals and contents . . . . . . . . . . . . . . . . . . . . . . . . 10
2 Continuous phase flow computation 13
2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2.2 Turbulent scales . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
2.3 Governing equations . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
2.3.1 Reynolds-Averaged Navier-Stokes Models . . . . . . . . . . . . 19
2.3.2 Standard k−ǫ turbulence model . . . . . . . . . . . . . . . . 22
2.3.3 Reynolds Stress Model . . . . . . . . . . . . . . . . . . . . . . 25
2.4 Large Eddy Simulation model (LES) and Smagorinsky model . . . . . 27
2.5 Solution algorithm . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
3 Dispersed Phase Motion 35
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
3.2 Coupling between phases . . . . . . . . . . . . . . . . . . . . . . . . . 36
3.3 Classification parameters of gas-particle flows . . . . . . . . . . . . . 36
3.4 Euler-Lagrangian approach . . . . . . . . . . . . . . . . . . . . . . . . 38
3.4.1 Equations for the particle rotation. . . . . . . . . . . . . . . . 46
v3.4.2 Influence of fluid turbulence on the particle movement . . . . 47
3.4.3 of particles on the fluid movement . . . . . . . . . . 49
3.5 Particle/wall collisions . . . . . . . . . . . . . . . . . . . . . . . . . . 51
3.6 Computation of the dispersed phase flow . . . . . . . . . . . . . . . . 55
3.6.1 Trajectory computation . . . . . . . . . . . . . . . . . . . . . 55
3.6.2 Simultaneous particle tracking . . . . . . . . . . . . . . . . . . 56
3.7 Solution algorithm . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
4 Validation process and computational results of cyclone flows 58
4.1 Validation Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
4.1.1 Channel flow . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
4.1.2 Flow and geometry descriptions . . . . . . . . . . . . . . . . . 60
4.1.3 Computational parameters . . . . . . . . . . . . . . . . . . . . 61
4.1.4 Periodic boundary condition . . . . . . . . . . . . . . . . . . . 62
4.1.5 Wall boundary conditions . . . . . . . . . . . . . . . . . . . . 62
4.1.6 Results and discussions . . . . . . . . . . . . . . . . . . . . . 63
4.2 Cyclone Flows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
4.2.1 Computational parameters . . . . . . . . . . . . . . . . . . . . 69
4.2.2 Continuous flow predictions (Cyclone A) . . . . . . . . . . . . 73
4.2.3 Pressure drop (Cyclone A) . . . . . . . . . . . . . . . . . . . . 87
4.2.4 Continuous flow predictions (Cyclone B) . . . . . . . . . . . . 91
4.3 Dispersed phase motion . . . . . . . . . . . . . . . . . . . . . . . . . 96
4.3.1 Cyclone separation efficiency (Cyclone A) . . . . . . . . . . . 97
4.3.2 Particle trajectories (Cyclone A) . . . . . . . . . . . . . . . . 98
4.4 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
5 Concluding Remarks and future work 102
List of Figures 108
Bibliography 109
viList of Tables
4.1 Cyclone dimensions in mm . . . . . . . . . . . . . . . . . . . . . . . 70
4.2 Computed variables . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
viiix
Latin symbols
Symbol Meaning
+A van Driest factor
a Cyclone inlet duct width
b inlet duct height
D Cyclone diameter, dissipation length scale
D Outlet pipe diametere
′ ′
D Convection and diffusion of u uij i j
D/D Total time derivativet
E Energy spectrum
c Magnus force factorM
c Saffman force factorS
c Drag force coefficientW
c Virtual mass force factorVM
c Rotation factorω
d Particle diameterP
e Impact number of particle wall impactw
~F Gravitational forceG
~F Magnus forceM
~F Saffman forceS
~F Drag forceW
~F Surface forceσ
f Wall damping functionu
~g,g ,g ,g Gravity forcex y z
G Convolution kernel
H Mean roughness depthr
I Moment of inertia of the particleP
k Kinetic energy of turbulence
L Size of a turbulence eddyE
L Mean cycle of roughnessr
l Integral length scale
m Particle massP
m Fluid massFx
m˙ ,m˙ Fluid and particle flow rateF P
→−n,n ,n ,n Normal vectorx y z
˙N Particle stream along a trajectoryP
N Number of trajectoriesT
N Local number of particles per package and/or cellP
˙N (d ) Inlet particle flow ratein P
˙N (d ) Outlet particle flow rateout P
P Perimeter
p Static pressure
′ ′
P Production of u uij i j
P Production term for k−ǫ equationk
Q ,Q Particle source terms for the impulse equationsP Pu v
S Geometrical swirl numberg
T Temperature, average interval
T Separation ratedP
T Transit time of a turbulence eddyD
T Eddy life spanE
T Turbulence intensityu
t Time
′ ′ ′u ,v ,w Fluctuation of fluid speedF F F
~v ,u ,v ,w Temporally averaged fluid speedF F F F
~v ,u ,v ,w Particle velocityP P P P
u u Reynolds-stress tensori j
~v Fluid velocity
v Relative velocity between particle surface and wallr
~v Relative velocity between particle and fluidrel
~V Velocity vector
V Particle volumeP
x,y,z Cartesian coordinates