Preface i Nomenclature iii Introduction v
1. Some Fundamentals of Dispersed
Multiphase Flows 1
1.1 Particle/Spray
Basic Properties 1
1.1.1 Particle/Droplet
Size and Its Distribution 1
1.1.2 Apparent
Density and Volume Fraction 2
1.2 Particle
Drag, Heat, and Mass Transfer 2
1.3 Single-Particle
Dynamics 3
1.3.1
1.3.2
1.3.3
1.3.4
1.3.5
1.3.6
References
Single-Particle Motion Equation 3 Motion of
a Single Particle in a Uniform Flow Field 4 Particle Gravitational Deposition 4
Forces Acting on Particles in Nonuniform Flow Field 5
1.3.4.1 Magnus
Force 5
1.3.4.2 Saffman Force 5
1.3.4.3 Particle
Thermophoresis, Electrophoresis, and Photophoresis 5 Generalized Particle
Motion Equation 6 Recent Studies on Particle Dynamics 6 7
Further Reading 8
2. Basic Concepts and Description of
Turbulence 9
2.1 Introduction
9
2.2 Time
Averaging 9
2.3 Probability
Density Function 10
2.4 Correlations, Length, and Time Scales
12 References 13
3. Fundamentals of Combustion Theory 15
3.1 Combustion
and Flame 15
3.2 Basic
Equations of Laminar Multicomponent Reacting Flows and Combustion 16
3.2.1 Thermodynamic
Relationships of Multicomponent Gases 16
xiii
3.2.2 Molecular
Transport Laws of Multicomponent Reacting Gases 18
3.2.3 Basic
Relationships of Chemical Kinetics 19
3.2.4 The
Reynolds Transport Theorem 20
3.2.5 Continuity
and Diffusion Equations 21
3.2.6 Momentum
Equation 22
3.2.7 Energy
Equation 23
3.2.8 Boundary
Conditions at the Interface and Stefan Flux 26
3.3 Ignition and Extinction 30
3.3.1 Basic
Concept 30
3.3.2 Dimensional
Analysis 30
3.3.3 Ignition
in an Enclosed Vessel—Simonov’s Unsteady Model 31
3.3.4 Ignition
Lag (Induction Period) 34
3.3.5 Ignition
by a Hot Plate—Khitrin-Goldenberg Model 35
3.3.6 Ignition
and Extinction—Vulis Model 37
3.4 Laminar Premixed and Diffusion
Combustion 41
3.4.1 Background
41
3.4.2 Basic
Equations and Their Properties 41
3.4.3 Two-Zone
Approximate Solution 43
3.4.4 Laminar
Diffusion Flame 46
3.5 Droplet Evaporation and Combustion 47
3.5.1 Background
47
3.5.2 Droplet
Evaporation in Stagnant Air 48
3.5.3 Basic
Equations for Droplet Evaporation and Combustion 48
3.5.4 Droplet
Evaporation With and Without Combustion 49
3.5.5 Droplet
Evaporation and Combustion under Forced Convection 50
3.5.6 The
d2 Law 52
3.5.7 Experimental
Results 52
3.5.8 Droplet
Ignition and Extinction 54
3.6 Solid-Fuel: Coal-Particle Combustion 54
3.6.1 Background
54
3.6.2 Coal
Pyrolyzation (Devolatilization) 55
3.6.3 Carbon
Oxidation 56
3.6.4 Carbon
Oxidation—Basic Equations 56
3.6.5 Carbon
Oxidation—Single-Flame-Surface Model-Only Reaction 1 or 2 at the Surface 57
3.6.6 Carbon
Oxidation—Two-Flame-Surface Model 60
3.6.7 Coal-Particle
Combustion 62
3.7 Turbulent Combustion and Flame
Stabilization 64
3.7.1 Background
64
3.7.2 Turbulent
Jet Diffusion Flame 64
3.7.3 Turbulent
Premixed Flame—Damkohler-Shelkin’s Wrinkled-Flame Model 66
Contents xY
3.7.4 Turbulent
Premixed Flame—Summerfield-Shetinkov’s Volume Combustion Model 67
3.7.5 Flame
Stabilization 67
3.8 Conclusion on Combustion Fundamentals
69 References 69
4. Basic
Equations of Multiphase Turbulent Reacting Flows 71
4.1 The
Control Volume in a Multiphase-Flow System 71
4.2 The
Concept of Volume Averaging 72
4.3 “Microscopic”
Conservation Equations Inside Each Phase 73
4.4 The
Volume-Averaged Conservation Equations for Laminar/Instantaneous Multiphase
Flows 73
4.5 The
Reynolds-Averaged Equations for Dilute Multiphase Turbulent Reacting Flows 78
4.6 The
PDF Equations for Turbulent Two-Phase Flows and Statistically Averaged
Equations 80
4.7 The
Two-Phase Reynolds Stress and Scalar Transport Equations 83 References 87
5. Modeling
of Single-Phase Turbulence 89
5.1 Introduction
89
5.2 The
Closure of Single-Phase Turbulent Kinetic Energy Equation 90
5.3 The
k-ε Two-Equation Model and Its Application 92
5.4 The
Second-Order Moment Closure of Single-Phase Turbulence 96
5.5 The
Closed Model of Reynolds Stresses and Heat Fluxes 99
5.6 The
Algebraic Stress and Flux Models—Extended k-ε Model 101
5.7 The
Application of DSM and ASM Models and Their Comparison with Other Models 103
5.8 Large-Eddy
Simulation 112
5.8.1 Filtration
112
5.8.2 SGS
Stress Models 113
5.8.3 LES
of Swirling Gas Flows 114
5.9 Direct Numerical Simulation 116
References 119
6. Modeling
of Dispersed Multiphase Turbulent Flows 121
6.1 Introduction
121
6.2 The
Hinze-Tchen’s Algebraic Model of Particle Turbulence 124
6.3 The
Unified Second-Order Moment Two-Phase Turbulence Model 124
6.4 The
k 2 ε 2 kp and k 2 ε 2 Ap Two-Phase Turbulence Model 128
6.5 The
Application and Validation of USM, k 2 ε 2 kp -kpg and k 2 ε 2 Ap Models 129
6.6 An
Improved Second-Order Moment Two-Phase Turbulence Model 134
6.7 The
Mass-Weighted Averaged USM Two-Phase Turbulence Model 136
6.8 The
DSM-PDF and k 2 ε-PDF Two-Phase Turbulence Models 141
6.9 An
SOM-MC Model of Swirling Gas-Particle Flows 144
6.10 The
Nonlinear k 2 ε 2 kp Two-Phase Turbulence Model 146
6.11 The
Kinetic Theory Modeling of Dense Particle (Granular) Flows 150
6.12 Two-Phase
Turbulence Models for Dense Gas-Particle Flows 153
6.13 The
Eulerian-Lagrangian Simulation of Gas-Particle Flows 155
6.13.1 Governing
Equations for the Deterministic Trajectory Model 156
6.13.2 Modification
for Particle Turbulent Diffusion 157
6.13.3 The
Stochastic Trajectory Model 159
6.13.4 The
DEM Simulation of Dense Gas-Particle Flows 161
6.14 The
Large-Eddy Simulation of Turbulent Gas-Particle Flows 163
6.14.1 Eulerian-Lagrangian
LES of Swirling Gas-Particle Flows 165
6.14.2 Eulerian-Lagrangian
LES of Bubble-Liquid Flows 166
6.14.3 Two-Fluid
LES of Swirling Gas-Particle Flows 167
6.14.4 Application
of LES in Engineering Gas-Particle Flows 170
6.15 The
Direct Numerical Simulation of Dispersed Multiphase Flows 172 References 177
7. Modeling
of Turbulent Combustion 183
7.1 Introduction
183
7.2 The
Time-Averaged Reaction Rate 183
7.3 The
Eddy-Break-Up (EBU) Model/Eddy Dissipation Model (EDM) 184
7.4 The
Presumed PDF Models 186
7.4.1 The
Probability Density Distribution Function 186
7.4.2 The
Simplified PDF-Local Instantaneous Nonpremixed Fast-Chemistry Model 187
7.4.3 The
Simplified PDF-Local Instantaneous Equilibrium Model 191
7.4.4 The
Simplified-PDF Finite-Rate Model 194
7.5 The
PDF Transport Equation Model 198
7.6 The
Bray-Moss-Libby (BML) Model 200
7.7 The
Conditional Moment Closure (CMC) Model 201
7.8 The
Laminar-Flamelet Model 202
Contents xYii
7.9 The
Second-Order Moment Combustion Model 204
7.9.1 The Early Developed Second-Order
Moment Model 204
7.9.2 An Updated Second-Order Moment (SOM)
Model 207
7.9.3 Application of the SOM Model in RANS
Modeling 208
7.9.4 Validation of the SOM Model by DNS 212
7.10 Modeling
of Turbulent Two-Phase Combustion 215
7.10.1 Two-Fluid
Modeling of Turbulent Two-Phase Combustion 216
7.10.2 Two-Fluid-Simulation
of Coal Combustion in a Combustor with High-Velocity Jets 218
7.10.3 Two-Fluid
Modeling of Coal Combustion and NO Formation in a Swirl Combustor 221
7.10.4 Eulerian-Lagrangian
Modeling of Two-Phase Combustion 223
7.11 Large-Eddy
Simulation of Turbulent Combustion 224
7.11.1 LES
Equations and Closure Models for Simulating Gas Turbulent Combustion 224
7.11.2 LES
of Swirling Diffusion Combustion, Jet Diffusion Combustion, and Bluff-Body
Premixed Combustion 226
7.11.3 LES
of Ethanol-Air Spray Combustion 232
7.11.4 LES
of Swirling Coal Combustion 235
7.12 Direct Numerical Simulation of
Turbulent Combustion 242 References 249
8. The
Solution Procedure for Modeling Multiphase Turbulent Reacting Flows 253
8.1 The
PSIC Algorithm for Eulerian-Lagrangian Models 253
8.2 The
LEAGAP Algorithm for E-E-L Modeling 256
8.3 The
PERT Algorithm for Eulerian-Eulerian Modeling 257
8.4 The
GENMIX-2P and IPSA Algorithms for Eulerian-Eulerian Modeling 257 References 260
9. Simulation
of Flows and Combustion in Practical Fluid Machines, Combustors, and Furnaces
261
9.1 An
Oil-Water Hydrocyclone 261
9.2 A
Gas-Solid Cyclone Separator 262
9.3 A
Nonslagging Vortex Coal Combustor 266
9.4 A
Spouting-Cyclone Coal Combustor 268
9.5 Pulverized-Coal
Furnaces 273
9.6 Spray
Combustors 290
9.7 Concluding Remarks 307 References 308
Index 311
