Hjem

Symbols xxi
CHAPTER 1 Introduction
1
1.
1 What and How? 2
1.
2 Physical Origins and Rate Equations 3
1.
2.
1 Conduction 3
1.
2.
2 Convection 6
1.
2.
3 Radiation 8
1.
2.
4 The Thermal Resistance Concept 12
1.
3 Relationship to Thermodynamics 12
1.
3.
1 Relationship to the First Law of Thermodynamics (Conservation of Energy) 13
1.
3.
2 Relationship to the Second Law of Thermodynamics and the Efficiency of Heat Engines 31
1.
4 Units and Dimensions 36
1.
5 Analysis of Heat Transfer Problems: Methodology 38
1.
6 Relevance of Heat Transfer 41
1.
7 Summary 45 References 48 Problems 49
CHAPTER 2 Introduction to Conduction 67
2.
1 The Conduction Rate Equation 68
2.
2 The Thermal Properties of Matter 70
2.
2.
1 Thermal Conductivity 70
2.
2.
2 Other Relevant Properties 78
2.
3 The Heat Diffusion Equation 82
2.
4 Boundary and Initial Conditions 90
2.
5 Summary 94 References 95 Problems 95
CHAPTER 3 One-Dimensional, Steady-State Conduction 111
3.
1 The Plane Wall 112
3.
1.
1 Temperature Distribution 112
3.
1.
2 Thermal Resistance 114
3.
1.
3 The Composite Wall 115
3.
1.
4 Contact Resistance 117
3.
1.
5 Porous Media 119
3.
2 An Alternative Conduction Analysis 132
3.
3 Radial Systems 136
3.
3.
1 The Cylinder 136
3.
3.
2 The Sphere 141
3.
4 Summary of One-Dimensional Conduction Results 142
3.
5 Conduction with Thermal Energy Generation 142
3.
5.
1 The Plane Wall 143
3.
5.
2 Radial Systems 149
3.
5.
3 Tabulated Solutions 150
3.
5.
4 Application of Resistance Concepts 150
3.
6 Heat Transfer from Extended Surfaces 154
3.
6.
1 A General Conduction Analysis 156
3.
6.
2 Fins of Uniform Cross-Sectional Area 158
3.
6.
3 Fin Performance 164
3.
6.
4 Fins of Nonuniform Cross-Sectional Area 167
3.
6.
5 Overall Surface Efficiency 170
3.
7 The Bioheat Equation 178
3.
8 Thermoelectric Power Generation 182
3.
9 Micro- and Nanoscale Conduction 189
3.
9.
1 Conduction Through Thin Gas Layers 189
3.
9.
2 Conduction Through Thin Solid Films 190
3.
10 Summary 190 References 193 Problems 193
CHAPTER 4 Two-Dimensional, Steady-State Conduction 229
4.
1 Alternative Approaches 230
4.
2 The Method of Separation of Variables 231
4.
3 The Conduction Shape Factor and the Dimensionless Conduction Heat Rate 235
4.
4 Finite-Difference Equations 241
4.
4.
1 The Nodal Network 241
4.
4.
2 Finite-Difference Form of the Heat Equation 242
4.
4.
3 The Energy Balance Method 243
4.
5 Solving the Finite-Difference Equations 250
4.
5.
1 Formulation as a Matrix Equation 250
4.
5.
2 Verifying the Accuracy of the Solution 251
4.
6 Summary 256 References 257 Problems 257 4S.
1 The Graphical Method W-1 4S.
1.
1 Methodology of Constructing a Flux Plot W-1 4S.
1.
2 Determination of the Heat Transfer Rate W-2 4S.
1.
3 The Conduction Shape Factor W-3 4S.
2 The Gauss Seidel Method: Example of Usage W-5 References W-9 Problems W-10
CHAPTER 5 Transient Conduction 279
5.
1 The Lumped Capacitance Method 280
5.
2 Validity of the Lumped Capacitance Method 283
5.
3 General Lumped Capacitance Analysis 287
5.
3.
1 Radiation Only 288
5.
3.
2 Negligible Radiation 288
5.
3.
3 Convection Only with Variable Convection Coefficient 289
5.
3.
4 Additional Considerations 289
5.
4 Spatial Effects 298
5.
5 The Plane Wall with Convection 299
5.
5.
1 Exact Solution 300
5.
5.
2 Approximate Solution 300
5.
5.
3 Total Energy Transfer 302
5.
5.
4 Additional Considerations 302
5.
6 Radial Systems with Convection 303
5.
6.
1 Exact Solutions 303
5.
6.
2 Approximate Solutions 304
5.
6.
3 Total Energy Transfer 304
5.
6.
4 Additional Considerations 305
5.
7 The Semi-Infinite Solid 310
5.
8 Objects with Constant Surface Temperatures or Surface Heat Fluxes 317
5.
8.
1 Constant Temperature Boundary Conditions 317
5.
8.
2 Constant Heat Flux Boundary Conditions 319
5.
8.
3 Approximate Solutions 320
5.
9 Periodic Heating 327
5.
10 Finite-Difference Methods 330
5.
10.
1 Discretization of the Heat Equation: The Explicit Method 330
5.
10.
2 Discretization of the Heat Equation: The Implicit Method 337
5.
11 Summary 345 References 346 Problems 346 5S.
1 Graphical Representation of One-Dimensional, Transient Conduction in the Plane Wall, Long Cylinder, and Sphere W-12 5S.
2 Analytical Solution of Multidimensional Effects W-16 References W-22 Problems W-22
CHAPTER 6 Introduction to Convection 377
6.
1 The Convection Boundary Layers 378
6.
1.
1 The Velocity Boundary Layer 378
6.
1.
2 The Thermal Boundary Layer 379
6.
1.
3 Significance of the Boundary Layers 380
6.
2 Local and Average Convection Coefficients 381
6.
2.
1 Heat Transfer 381
6.
2.
2 The Problem of Convection 382
6.
3 Laminar and Turbulent Flow 383
6.
3.
1 Laminar and Turbulent Velocity Boundary Layers 383
6.
3.
2 Laminar and Turbulent Thermal Boundary Layers 385
6.
4 The Boundary Layer Equations 388
6.
4.
1 Boundary Layer Equations for Laminar Flow 389
6.
4.
2 Compressible Flow 391
6.
5 Boundary Layer Similarity: The Normalized Boundary Layer Equations 392
6.
5.
1 Boundary Layer Similarity Parameters 392
6.
5.
2 Functional Form of the Solutions 393
6.
6 Physical Interpretation of the Dimensionless Parameters 400
6.
7 Momentum and Heat Transfer (Reynolds) Analogy 402
6.
8 Summary 404 References 405 Problems 405 6S.
1 Derivation of the Convection Transfer Equations W-25 6S.
1.
1 Conservation of Mass W-25 6S.
1.
2 Newton s Second Law of Motion W-26 6S.
1.
3 Conservation of Energy W-29 References W-35 Problems W-35
CHAPTER 7 External Flow 415
7.
1 The Empirical Method 416
7.
2 The Flat Plate in Parallel Flow 418
7.
2.
1 Laminar Flow over an Isothermal Plate: A Similarity Solution 418
7.
2.
2 Turbulent Flow over an Isothermal Plate 424
7.
2.
3 Mixed Boundary Layer Conditions 425
7.
2.
4 Unheated Starting Length 426
7.
2.
5 Flat Plates with Constant Heat Flux Conditions 427
7.
2.
6 Limitations on Use of Convection Coefficients 427
7.
3 Methodology for a Convection Calculation 428
7.
4 The Cylinder in Cross Flow 433
7.
4.
1 Flow Considerations 433
7.
4.
2 Convection Heat Transfer 436
7.
5 The Sphere 443
7.
6 Flow Across Banks of Tubes 447
7.
7 Impinging Jets 455
7.
7.
1 Hydrodynamic and Geometric Considerations 456
7.
7.
2 Convection Heat Transfer 458
7.
8 Packed Beds 461
7.
9 Summary 462 References 464 Problems 465
CHAPTER 8 Internal Flow 489
8.
1 Hydrodynamic Considerations 490
8.
1.
1 Flow Conditions 490
8.
1.
2 The Mean Velocity 491
8.
1.
3 Velocity Profile in the Fully Developed Region 492
8.
1.
4 Pressure Gradient and Friction Factor in Fully Developed Flow 494
8.
2 Thermal Considerations 495
8.
2.
1 The Mean Temperature 496
8.
2.
2 Newton s Law of Cooling 497
8.
2.
3 Fully Developed Conditions 497
8.
3 The Energy Balance 501
8.
3.
1 General Considerations 501
8.
3.
2 Constant Surface Heat Flux 502
8.
3.
3 Constant Surface Temperature 505
8.
4 Laminar Flow in Circular Tubes: Thermal Analysis and Convection Correlations 509
8.
4.
1 The Fully Developed Region 509
8.
4.
2 The Entry Region 514
8.
4.
3 Temperature-Dependent Properties 516
8.
5 Convection Correlations: Turbulent Flow in Circular Tubes 516
8.
6 Convection Correlations: Noncircular Tubes and the Concentric Tube Annulus 524
8.
7 Heat Transfer Enhancement 527
8.
8 Flow in Small Channels 530
8.
8.
1 Microscale Convection in Gases (0.
1 m Dh 100 m) 530
8.
8.
2 Microscale Convection in Liquids 531
8.
8.
3 Nanoscale Convection (Dh 100 nm) 532
8.
9 Summary 535 References 537 Problems 538
CHAPTER 9 Free Convection 561
9.
1 Physical Considerations 562
9.
2 The Governing Equations for Laminar Boundary Layers 565
9.
3 Similarity Considerations 566
9.
4 Laminar Free Convection on a Vertical Surface 567
9.
5 The Effects of Turbulence 570
9.
6 Empirical Correlations: External Free Convection Flows 572
9.
6.
1 The Vertical Plate 573
9.
6.
2 Inclined and Horizontal Plates 576
9.
6.
3 The Long Horizontal Cylinder 581
9.
6.
4 Spheres 585
9.
7 Free Convection Within Parallel Plate Channels 586
9.
7.
1 Vertical Channels 587
9.
7.
2 Inclined Channels 589
9.
8 Empirical Correlations: Enclosures 589
9.
8.
1 Rectangular Cavities 589
9.
8.
2 Concentric Cylinders 592
9.
8.
3 Concentric Spheres 593
9.
9 Combined Free and Forced Convection 595
9.
10 Summary 596 References 597 Problems 598
CHAPTER 10 Boiling and Condensation 619
10.
1 Dimensionless Parameters in Boiling and Condensation 620
10.
2 Boiling Modes 621
10.
3 Pool Boiling 622
10.
3.
1 The Boiling Curve 622
10.
3.
2 Modes of Pool Boiling 623
10.
4 Pool Boiling Correlations 626
10.
4.
1 Nucleate Pool Boiling 626
10.
4.
2 Critical Heat Flux for Nucleate Pool Boiling 628
10.
4.
3 Minimum Heat Flux 629
10.
4.
4 Film Pool Boiling 629
10.
4.
5 Parametric Effects on Pool Boiling 630
10.
5 Forced Convection Boiling 635
10.
5.
1 External Fo