Syllabus For The Subject Multi phase Contractors

 

Multi phase Contractors

 

Contents

Preface page 2

Contents 10

Nomenclature 11

1 INTRODUCTIONTOMULTIPHASEFLOW 19

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

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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

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4.4.2 Nonlinear effects 124

4.4.3 Rectified mass diffusion 126

5 CAVITATION 128

5.1 INTRODUCTION 128

5.2 KEY FEATURES OF BUBBLE CAVITATION 128

5.2.1 Cavitation inception 128

5.2.2 Cavitation bubble collapse 131

5.2.3 Shape distortion during bubble collapse 133

5.2.4 Cavitation damage 136

5.3 CAVITATION BUBBLES 139

5.3.1 Observations of cavitating bubbles 139

5.3.2 Cavitation noise 142

5.3.3 Cavitation luminescence 149

6 BOILING AND CONDENSATION 150

6.1 INTRODUCTION 150

6.2 HORIZONTAL SURFACES 151

6.2.1 Pool boiling 151

6.2.2 Nucleate boiling 153

6.2.3 Film boiling 154

6.2.4 Leidenfrost effect 155

6.3 VERTICAL SURFACES 157

6.3.1 Film boiling 158

6.4 CONDENSATION 160

6.4.1 Film condensation 160

7 FLOW PATTERNS 163

7.1 INTRODUCTION 163

7.2 TOPOLOGIES OF MULTIPHASE FLOW 163

7.2.1 Multiphase flow patterns 163

7.2.2 Examples of flow regime maps 165

7.2.3 Slurry flow regimes 168

7.2.4 Vertical pipe flow 169

7.2.5 Flow pattern classifications 173

7.3 LIMITS OF DISPERSE FLOW REGIMES 174

7.3.1 Disperse phase separation and dispersion 174

7.3.2 Example: horizontal pipe flow 176

7.3.3 Particle size and particle fission 178

7.3.4 Examples of flow-determined bubble size 179

7.3.5 Bubbly or mist flow limits 181

7.3.6 Other bubbly flow limits 182

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7.3.7 Other particle size effects 183

7.4 INHOMOGENEITY INSTABILITY 184

7.4.1 Stability of disperse mixtures 184

7.4.2 Inhomogeneity instability in vertical flows 187

7.5 LIMITS ON SEPARATED FLOW 191

7.5.1 Kelvin-Helmoltz instability 192

7.5.2 Stratified flow instability 194

7.5.3 Annular flow instability 194

8 INTERNAL FLOW ENERGY CONVERSION 196

8.1 INTRODUCTION 196

8.2 FRICTIONAL LOSS IN DISPERSE FLOW 196

8.2.1 Horizontal Flow 196

8.2.2 Homogeneous flow friction 199

8.2.3 Heterogeneous flow friction 201

8.2.4 Vertical flow 203

8.3 FRICTIONAL LOSS IN SEPARATED FLOW 205

8.3.1 Two component flow 205

8.3.2 Flow with phase change 211

8.4 ENERGY CONVERSION IN PUMPS AND TURBINES 215

8.4.1 Multiphase flows in pumps 215

9 HOMOGENEOUS FLOWS 220

9.1 INTRODUCTION 220

9.2 EQUATIONS OF HOMOGENEOUS FLOW 220

9.3 SONIC SPEED 221

9.3.1 Basic analysis 221

9.3.2 Sonic speeds at higher frequencies 225

9.3.3 Sonic speed with change of phase 227

9.4 BAROTROPIC RELATIONS 231

9.5 NOZZLE FLOWS 233

9.5.1 One dimensional analysis 233

9.5.2 Vapor/liquid nozzle flow 238

9.5.3 Condensation shocks 242

10 FLOWS WITH BUBBLE DYNAMICS 246

10.1 INTRODUCTION 246

10.2 BASIC EQUATIONS 247

10.3 ACOUSTICS OF BUBBLY MIXTURES 248

10.3.1 Analysis 248

10.3.2 Comparison with experiments 250

10.4 SHOCK WAVES IN BUBBLY FLOWS 253

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10.4.1 Normal shock wave analysis 253

10.4.2 Shock wave structure 256

10.4.3 Oblique shock waves 259

10.5 FINITE BUBBLE CLOUDS 259

10.5.1 Natural modes of a spherical cloud of bubbles 259

10.5.2 Response of a spherical bubble cloud 264

11 FLOWS WITH GAS DYNAMICS 267

11.1 INTRODUCTION 267

11.2 EQUATIONS FOR A DUSTY GAS 268

11.2.1 Basic equations 268

11.2.2 Homogeneous flow with gas dynamics 269

11.2.3 Velocity and temperature relaxation 271

11.3 NORMAL SHOCK WAVE 272

11.4 ACOUSTIC DAMPING 275

11.5 LINEAR PERTURBATION ANALYSES 279

11.5.1 Stability of laminar flow 279

11.5.2 Flow over a wavy wall 280

11.6 SMALL SLIP PERTURBATION 282

12 SPRAYS 285

12.1 INTRODUCTION 285

12.2 TYPES OF SPRAY FORMATION 285

12.3 OCEAN SPRAY 286

12.4 SPRAY FORMATION 288

12.4.1 Spray formation by bubbling 288

12.4.2 Spray formation by wind shear 289

12.4.3 Spray formation by initially laminar jets 292

12.4.4 Spray formation by turbulent jets 293

12.5 SINGLE DROPLET MECHANICS 299

12.5.1 Single droplet evaporation 299

12.5.2 Single droplet combustion 301

12.6 SPRAY COMBUSTION 305

13 GRANULAR FLOWS 308

13.1 INTRODUCTION 308

13.2 PARTICLE INTERACTION MODELS 309

13.2.1 Computer simulations 311

13.3 FLOW REGIMES 312

13.3.1 Dimensional Analysis 312

13.3.2 Flow regime rheologies 313

13.3.3 Flow regime boundaries 316

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13.4 SLOW GRANULAR FLOW 317

13.4.1 Equations of motion 317

13.4.2 Mohr-Coulomb models 317

13.4.3 Hopper flows 318

13.5 RAPID GRANULAR FLOW 320

13.5.1 Introduction 320

13.5.2 Example of rapid flow equations 322

13.5.3 Boundary conditions 325

13.5.4 Computer simulations 326

13.6 EFFECT OF INTERSTITIAL FLUID 326

13.6.1 Introduction 326

13.6.2 Particle collisions 327

13.6.3 Classes of interstitial fluid effects 329

14 DRIFT FLUX MODELS 331

14.1 INTRODUCTION 331

14.2 DRIFT FLUX METHOD 332

14.3 EXAMPLES OF DRIFT FLUX ANALYSES 333

14.3.1 Vertical pipe flow 333

14.3.2 Fluidized bed 336

14.3.3 Pool boiling crisis 338

14.4 CORRECTIONS FOR PIPE FLOWS 343

15 SYSTEM INSTABILITIES 344

15.1 INTRODUCTION 344

15.2 SYSTEM STRUCTURE 344

15.3 QUASISTATIC STABILITY 347

15.4 QUASISTATIC INSTABILITY EXAMPLES 349

15.4.1 Turbomachine surge 349

15.4.2 Ledinegg instability 349

15.4.3 Geyser instability 350

15.5 CONCENTRATION WAVES 351

15.6 DYNAMIC MULTIPHASE FLOW INSTABILITIES 353

15.6.1 Dynamic instabilities 353

15.6.2 Cavitation surge in cavitating pumps 354

15.6.3 Chugging and condensation oscillations 356

15.7 TRANSFER FUNCTIONS 359

15.7.1 Unsteady internal flow methods 359

15.7.2 Transfer functions 360

15.7.3 Uniform homogeneous flow 362

16 KINEMATIC WAVES 365

16.1 INTRODUCTION 365

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16.2 TWO-COMPONENT KINEMATIC WAVES 366

16.2.1 Basic analysis 366

16.2.2 Kinematic wave speed at flooding 368

16.2.3 Kinematic waves in steady flows 369

16.3 TWO-COMPONENT KINEMATIC SHOCKS 370

16.3.1 Kinematic shock relations 370

16.3.2 Kinematic shock stability 372

16.3.3 Compressibility and phase change effects 374

16.4 EXAMPLES OF KINEMATIC WAVE ANALYSES 375

16.4.1 Batch sedimentation 375

16.4.2 Dynamics of cavitating pumps 378

16.5 TWO-DIMENSIONAL SHOCKS 383

Bibliography 385

Index 407

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