Fundamentals of Thermal-Fluid Sciences, Sixth Edition
By Yunus A. Çengel, John M. Cimbala, and Afshin J. Ghajar
Contents:
Preface xiv
Chapter One
INTRODUCTION AND OVERVIEW 1
1–1 Introduction to Thermal‑Fluid Sciences 2
Application Areas of Thermal‑Fluid Sciences 2
1–2 Thermodynamics 3
1–3 Heat Transfer 4
1–4 Fluid Mechanics 5
1–5 Importance of Dimensions and Units 7
Some SI and English Units 8
Dimensional Homogeneity 10
Unity Conversion Ratios 12
1–6 Problem-Solving Technique 12
Step 1: Problem Statement 13
Step 2: Schematic 13
Step 3: Assumptions and Approximations 13
Step 4: Physical Laws 13
Step 5: Properties 13
Step 6: Calculations 13
Step 7: Reasoning, Verification, and Discussion 13
Engineering Software Packages 14
Equation Solvers 15
A Remark on Significant Digits 16
Summary 17
References and Suggested Readings 17
problems 17
PART 1 THERMODYNAMICS 19
Chapter Two
BASIC CONCEPTS OF THERMODYNAMICS 21
2–1 Systems and Control Volumes 22
2–2 Properties of a System 23
Continuum 23
2–3 Density and Specific Gravity 24
2–4 State and Equilibrium 25
The State Postulate 25
2–5 Processes and Cycles 26
The Steady-Flow Process 27
2–6 Temperature and the Zeroth Law of Thermodynamics 27
Temperature Scales 28
2–7 Pressure 31
Variation of Pressure with Depth 32
2–8 Pressure Measurement Devices 35
The Barometer 35
The Manometer 38
Other Pressure Measurement Devices 40
Summary 41
References and Suggested Readings 42
Problems 42
Chapter Three
ENERGY, ENERGY TRANSFER, AND GENERAL ENERGY ANALYSIS 49
3–1 Introduction 50
3–2 Forms of Energy 51
Some Physical Insight into Internal Energy 52
More on Nuclear Energy 54
Mechanical Energy 55
3–3 Energy Transfer by Heat 57
Historical Background on Heat 58
3–4 Energy Transfer By Work 59
Electrical Work 61
3–5 Mechanical Forms Of Work 62
Shaft Work 62
Spring Work 63
Work Done on Elastic Solid Bars 63
Work Associated with the Stretching of a Liquid Film 64
Work Done to Raise or to Accelerate a Body 64
Nonmechanical Forms of Work 65
3–6 The First Law Of Thermodynamics 65
Energy Balance 67
Energy Change of a System, ΔEsystem 67
Mechanisms of Energy Transfer, Ein and Eout 68
3–7 Energy Conversion Efficiencies 72
Efficiencies of Mechanical and Electrical Devices 76
Summary 79
References and Suggested Readings 80
Problems 80
Chapter Four
PROPERTIES OF PURE SUBSTANCES 87
4–1 Pure Substance 88
4–2 Phases of a Pure Substance 88
4–3 Phase-Change Processes of Pure Substances 89
Compressed Liquid and Saturated Liquid 89
Saturated Vapor and Superheated Vapor 90
Saturation Temperature and Saturation Pressure 90
Some Consequences of Tsat and Psat Dependence 92
4–4 Property Diagrams for Phase-Change Processes 93
1 The T-v Diagram 93
2 The P-v Diagram 94
Extending the Diagrams to Include the Solid Phase 95
3 The P-T Diagram 97
The P-v-T Surface 97
4–5 Property Tables 98
Enthalpy—A Combination Property 98
1a Saturated Liquid and Saturated Vapor States 99
1b Saturated Liquid–Vapor Mixture 100
2 Superheated Vapor 103
3 Compressed Liquid 104
Reference State and Reference Values 106
4–6 The Ideal-Gas Equation of State 107
Is Water Vapor an Ideal Gas? 109
4–7 Compressibility Factor—A Measure of Deviation from Ideal- Gas Behavior 110
Summary 114
References and Suggested Readings 114
Problems 115
Chapter Five
ENERGY ANALYSIS OF CLOSED SYSTEMS 123
5–1 Moving Boundary Work 124
Polytropic Process 127
5–2 Energy Balance for Closed Systems 129
5–3 Specific Heats 133
5–4 Internal Energy, Enthalpy, and Specific Heats of Ideal Gases 134
Specific Heat Relations of Ideal Gases 136
5–5 Internal Energy, Enthalpy, and Specific Heats of Solids and Liquids 140
Internal Energy Changes 141
Enthalpy Changes 141
Summary 144
References and Suggested Readings 145
Problems 145
Chapter Six
MASS AND ENERGY ANALYSIS OF CONTROL VOLUMES 157
6–1 Conservation of Mass 158
Mass and Volume Flow Rates 158
Conservation of Mass Principle 159
Mass Balance for Steady-Flow Processes 161
Special Case: Incompressible Flow 162
6–2 Flow Work and the Energy of a Flowing
Fluid 164
Total Energy of a Flowing Fluid 165
Energy Transport by Mass 165
6–3 Energy Analysis of Steady-Flow Systems 167
6–4 Some Steady-Flow Engineering Devices 170
1 Nozzles and Diffusers 170
2 Turbines and Compressors 173
3 Throttling Valves 175
4a Mixing Chambers 176
4b Heat Exchangers 178
5 Pipe and Duct Flow 180
6–5 Energy Analysis of Unsteady-
Flow
Processes 181
Summary 186
References and Suggested Readings 187
Problems 187
Chapter Seven
THE SECOND LAW OF THERMODYNAMICS 203
7–1 Introduction to the Second Law 204
7–2 Thermal Energy Reservoirs 205
7–3 Heat Engines 205
Thermal Efficiency 207
Can We Save Qout? 208
The Second Law of Thermodynamics: Kelvin–Planck
Statement 210
7–4 Refrigerators and Heat Pumps 210
Coefficient of Performance 211
Heat Pumps 212
Performance of Refrigerators, Air Conditioners, and Heat
Pumps 213
The Second Law of Thermodynamics: Clausius
Statement 215
Equivalence of the Two Statements 215
7–5 Reversible and Irreversible Processes 216
Irreversibilities 217
Internally and Externally Reversible Processes 218
7–6 The Carnot Cycle 218
The Reversed Carnot Cycle 220
7–7 The Carnot Principles 220
7–8 The Thermodynamic Temperature Scale 221
7–9 The Carnot Heat Engine 223
The Quality of Energy 225
7–10 The Carnot Refrigerator and Heat Pump 225
Summary 228
References and Suggested Readings 229
Problems 229
Chapter Eight
ENTROPY 239
8–1 Entropy 240
A Special Case: Internally Reversible Isothermal Heat Transfer
Processes 242
8–2 The Increase of Entropy Principle 243
Some Remarks About Entropy 245
8–3 Entropy Change of Pure Substances 246
8–4 Isentropic Processes 249
8–5 Property Diagrams Involving Entropy 250
8–6 What is Entropy? 252
Entropy and Entropy Generation in Daily Life 254
8–7 The T ds Relations 255
8–8 Entropy Change of Liquids and Solids 256
8–9 The Entropy Change of Ideal Gases 259
Constant Specific Heats (Approximate Analysis) 260
Variable Specific Heats (Exact Analysis) 260
Isentropic Processes of Ideal Gases 262
Constant Specific Heats (Approximate Analysis) 262
Variable Specific Heats (Exact Analysis) 263
Relative Pressure and Relative Specific Volume 263
8–10 Reversible Steady-Flow Work 266
Proof that Steady-Flow Devices Deliver the Most and
Consume the Least Work When the Process Is
Reversible 269
8–11 Isentropic Efficiencies of Steady-Flow
Devices 269
Isentropic Efficiency of Turbines 270
Isentropic Efficiencies of Compressors and Pumps 271
Isentropic Efficiency of Nozzles 273
8–12 Entropy Balance 275
Entropy Change of a System, ΔS system 276
Mechanisms of Entropy Transfer, Sin and Sout 276
1 Heat Transfer 276
2 Mass Flow 277
Entropy Generation, Sgen 277
Closed Systems 278
Control Volumes 279
Summary 284
References and Suggested Readings 285
Problems 285
Chapter Nine
POWER AND REFRIGERATION CYCLES 301
9–1 Basic Considerations in the Analysis of Power Cycles 302
9–2 The Carnot Cycle and its Value in Engineering 304
9–3 Air-Standard Assumptions 305
9–4 An Overview of Reciprocating Engines 307
9–5 Otto Cycle: The Ideal Cycle for Spark-Ignition Engines 307
9–6 Diesel Cycle: The Ideal Cycle for Compression-
Ignition Engines 314
9–7 Brayton Cycle: The Ideal Cycle for Gas-Turbine
Engines 317
Development of Gas Turbines 319
Deviation of Actual Gas-Turbine Cycles from Idealized
Ones 321
9–8 The Brayton Cycle with Regeneration 323
9–9 The Carnot Vapor Cycle 325
9–10 Rankine Cycle: The Ideal Cycle for Vapor Power Cycles 326
Energy Analysis of the Ideal Rankine Cycle 327
9–11 Deviation of Actual Vapor Power Cycles
From Idealized Ones 329
9–12 How Can We Increase The Efficiency of The
Rankine Cycle? 331
Lowering the Condenser Pressure (Lowers Tlow,avg) 331
Superheating the Steam to High Temperatures (Increases
Thigh,avg) 332
Increasing the Boiler Pressure (Increases Thigh,avg) 332
9–13 The Ideal Reheat Rankine Cycle 335
9–14 Refrigerators and Heat Pumps 339
9–15 The Reversed Carnot Cycle 340
9–16 The Ideal Vapor-Compression Refrigeration
Cycle 341
9–17 Actual Vapor-Compression Refrigeration
Cycle 343
9–18 Heat Pump Systems 345
Summary 346
References and Suggested Readings 348
Problems 348
PART 2 FLUID MECHANICS 361
Chapter Ten
INTRODUCTION AND PROPERTIES OF FLUIDS 363
10–1 The No-Slip Condition 364
10–2 Classification of Fluid Flows 364
Viscous Versus Inviscid Regions of Flow 365
Internal Versus External Flow 365
Compressible Versus Incompressible Flow 365
Laminar Versus Turbulent Flow 366
Natural (or Unforced) Versus Forced Flow 366
Steady Versus Unsteady Flow 366
One-, Two-, and Three-Dimensional Flows 368
Uniform Versus Nonuniform Flow 369
10–3 Vapor Pressure and Cavitation 369
10–4 Viscosity 371
10–5 Surface Tension and Capillary Effect 375
Capillary Effect 378
Summary 381
References and Suggested Reading 381
Problems 381
Chapter Eleven
FLUID STATICS 387
11–1 Introduction to Fluid Statics 388
11–2 Hydrostatic Forces on Submerged Plane Surfaces 388
Special Case: Submerged Rectangular Plate 391
11–3 Hydrostatic Forces on Submerged Curved Surfaces 393
11–4 Buoyancy and Stability 396
Stability of Immersed and Floating Bodies 399
Summary 401
References and Suggested Reading 401
Problems 401
Chapter Twelve
BERNOULLI AND ENERGY EQUATIONS 409
12–1 The Bernoulli Equation 410
Acceleration of a Fluid Particle 410
Derivation of the Bernoulli Equation 411
Force Balance Across Streamlines 412
Unsteady, Compressible Flow 413
Static, Dynamic, and Stagnation Pressures 413
Limitations on the Use of the Bernoulli Equation 414
Hydraulic Grade Line (HGL) and Energy Grade Line
(EGL) 415
Applications of the Bernoulli Equation 417
12–2 Energy Analysis of Steady Flows 421
Special Case: Incompressible Flow with No Mechanical Work
Devices and Negligible Friction 423
Kinetic Energy Correction Factor, α 424
Summary 428
References and Suggested Reading 428
Problems 428
Chapter Thirteen
MOMENTUM ANALYSIS OF FLOW SYSTEMS 437
13–1 Newton’s Laws 438
13–2 Choosing a Control Volume 439
13–3 Forces Acting on a Control Volume 440
13–4 The Reynolds Transport Theorem 442
An Application: Conservation of Mass 446
13–5 The Linear Momentum Equation 446
Special Cases 448
Momentum-Flux Correction Factor, β 448
Steady Flow 450
Flow with No External Forces 451
Summary 457
References and Suggested Reading 457
Problems 458
Chapter Fourteen
INTERNAL FLOW 465
14–1 Introduction 466
14–2 Laminar and Turbulent Flows 467
Reynolds Number 467
14–3 The Entrance Region 468
Entry Lengths 469
14–4 Laminar Flow in Pipes 470
Pressure Drop and Head Loss 472
Effect of Gravity on Velocity and Flow Rate in Laminar Flow 474
Laminar Flow in Noncircular Pipes 475
14–5 Turbulent Flow in Pipes 478
Turbulent Velocity Profile 478
The Moody Chart and Its Associated Equations 478
Types of Fluid Flow Problems 480
14–6 Minor Losses 486
14–7 Piping Networks and Pump Selection 493
Series and Parallel Pipes 493
Piping Systems with Pumps and Turbines 494
Summary 499
References and Suggested Reading 501
Problems 501
Chapter Fifteen
EXTERNAL FLOW: DRAG AND LIFT 511
15–1 Introduction 512
15–2 Drag and Lift 514
15–3 Friction and Pressure Drag 517
Reducing Drag by Streamlining 518
Flow Separation 519
15–4 Drag Coefficients of Common Geometries 521
Biological Systems and Drag 522
Drag Coefficients of Vehicles 524
Superposition 525
15–5 Parallel Flow Over Flat Plates 527
Friction Coefficient 529
15–6 Flow Over Cylinders and Spheres 531
Effect of Surface Roughness 533
15–7 Lift 535
Finite-Span Wings and Induced Drag 539
Summary 542
References and Suggested Reading 543
Problems 543
PART 3 HEAT TRANSFER 551
Chapter Sixteen
MECHANISMS OF HEAT TRANSFER 553
16–1 Introduction 554
16–2 Conduction 554
Thermal Conductivity 555
Thermal Diffusivity 559
16–3 Convection 561
16–4 Radiation 563
16–5 Simultaneous Heat Transfer Mechanisms 565
Summary 569
References and Suggested Reading 570
Problems 570
Chapter Seventeen
STEADY HEAT CONDUCTION 579
17–1 Steady Heat Conduction in Plane Walls 580
Thermal Resistance Concept 581
Thermal Resistance Network 582
Multilayer Plane Walls 584
17–2 Thermal Contact Resistance 588
17–3 Generalized Thermal Resistance Networks 593
17–4 Heat Conduction in Cylinders and Spheres 595
Multilayered Cylinders and Spheres 597
17–5 Critical Radius of Insulation 601
17–6 Heat Transfer from Finned Surfaces 603
Fin Equation 604
Fin Efficiency 608
Fin Effectiveness 611
Proper Length of a Fin 613
Summary 617
References and Suggested Reading 618
Problems 618
Chapter Eighteen
TRANSIENT HEAT CONDUCTION 635
18–1 Lumped System Analysis 636
Criteria for Lumped System Analysis 637
Some Remarks on Heat Transfer in Lumped Systems 638
18–2 Transient Heat Conduction in Large Plane
Walls, Long Cylinders, and Spheres with Spatial
Effects 640
Nondimensionalized One-Dimensional Transient Conduction Problem 641
Approximate Analytical Solutions 643
18–3 Transient Heat Conduction in Semi-Infinite Solids 650
Contact of Two Semi-Infinite Solids 654
18–4 Transient Heat Conduction in Multidimensional Systems 657
Summary 662
References and Suggested Reading 663
Problems 663
Chapter Nineteen
FORCED CONVECTION 675
19–1 Physical Mechanism of Convection 676
Nusselt Number 678
19–2 Thermal Boundary Layer 678
Prandtl Number 679
19–3 Parallel Flow Over Flat Plates 679
Flat Plate with Unheated Starting Length 681
Uniform Heat Flux 682
19–4 Flow Across Cylinders and Spheres 685
19–5 General Considerations for Pipe Flow 688
Thermal Entrance Region 689
Entry Lengths 691
19–6 General Thermal Analysis 693
Constant Surface Heat Flux ( q • s = constant) 693
Constant Surface Temperature ( T s = constant) 694
19–7 Laminar Flow in Tubes 697
Constant Surface Heat Flux 697
Constant Surface Temperature 698
Laminar Flow in Noncircular Tubes 698
Developing Laminar Flow in the Entrance Region 699
19–8 Turbulent Flow in Tubes 701
Developing Turbulent Flow in the Entrance Region 703
Turbulent Flow in Noncircular Tubes 703
Flow Through Tube Annulus 703
Heat Transfer Enhancement 704
Summary 707
References and Suggested Reading 708
Problems 710
Chapter Twenty
NATURAL CONVECTION 723
20–1 Physical Mechanism of Natural Convection 724
20–2 Equation Of Motion and the Grash of Number 726
The Grashof Number 728
20–3 Natural Convection Over Surfaces 729
Vertical Plates (Ts = constant) 730
Vertical Plates ( q • s = constant) 730
Vertical Cylinders 732
Inclined Plates 732
Horizontal Plates 732
Horizontal Cylinders and Spheres 733
20–4 Natural Convection Inside Enclosures 736
Effective Thermal Conductivity 737
Horizontal Rectangular Enclosures 737
Inclined Rectangular Enclosures 738
Vertical Rectangular Enclosures 738
Concentric Cylinders 739
Combined Natural Convection and Radiation 740
Summary 743
References and Suggested Reading 744
Problems 745
Chapter Twenty one
RADIATION HEAT TRANSFER 757
21–1 Introduction 758
21–2 Thermal Radiation 759
21–3 Blackbody Radiation 760
21–4 Radiative Properties 766
Emissivity 767
Absorptivity, Reflectivity, and Transmissivity 770
Kirchhoff’s Law 772
The Greenhouse Effect 773
21–5 The View Factor 773
21–6 View Factor Relations 776
1 The Reciprocity Relation 777
2 The Summation Rule 779
3 The Superposition Rule 780
4 The Symmetry Rule 782
View Factors Between Infinitely Long Surfaces: The Crossed- Strings Method 783
21–7 Radiation Heat Transfer: Black Surfaces 785
21–8 Radiation Heat Transfer: Diffuse, Gray Surfaces 787
Radiosity 787
Net Radiation Heat Transfer to or from a Surface 787
Net Radiation Heat Transfer Between Any Two Surfaces 788
Methods of Solving Radiation Problems 789
Radiation Heat Transfer in Two-Surface Enclosures 790
Radiation Heat Transfer in Three-Surface Enclosures 792
Summary 795
References and Suggested Reading 796
Problems 797
Chapter Twenty Two
HEAT EXCHANGERS 809
22–1 Types of Heat Exchangers 810
22–2 The Overall Heat Transfer Coefficient 813
Fouling Factor 815
22–3 Analysis of Heat Exchangers 819
22–4 The Log Mean Temperature Difference Method 821
Counterflow Heat Exchangers 822
Multipass and Crossflow Heat Exchangers: Use of a Correction Factor 823
22–5 The Effectiveness–Ntu Method 829
Summary 839
References and Suggested Reading 839
Problems 840
Appendix 1
PROPERTY TABLES AND CHARTS (SI UNITS) 851
TABLE A–1 Molar mass, gas constant, and criticalpoint properties 852
TABLE A–2 Ideal-gas specific heats of various common gases 853
TABLE A–3 Properties of common liquids, solids, and foods 856
TABLE A–4 Saturated water—Temperature table 858
TABLE A–5 Saturated water—Pressure table 860
TABLE A–6 Superheated water 862
TABLE A–7 Compressed liquid water 866
TABLE A–8 Saturated ice–water vapor 867
FIGURE A–9 T-s diagram for water 868
FIGURE A–10 Mollier diagram for water 869
TABLE A–11 Saturated refrigerant-134a—Temperature table 870
TABLE A–12 Saturated refrigerant-134a—Pressure table 872
TABLE A–13 Superheated refrigerant-134a 873
FIGURE A–14 P-h diagram for refrigerant-134a 875
TABLE A–15 Properties of saturated water 876
TABLE A–16 Properties of saturated refrigerant- 134a 877
TABLE A–17 Properties of saturated ammonia 878
TABLE A–18 Properties of saturated propane 879
TABLE A–19 Properties of liquids 880
TABLE A–20 Properties of liquid metals 881
TABLE A–21 Ideal-gas properties of air 882
TABLE A–22 Properties of air at 1 atm pressure 884
TABLE A–23 Properties of gases at 1 atm pressure 885
TABLE A–24 Properties of solid metals 887
TABLE A–25 Properties of solid nonmetals 890
TABLE A–26 Emissivities of surfaces 891
FIGURE A–27 The Moody chart 893
FIGURE A–28 Nelson–Obert generalized compressibility chart 894
Appendix 2
PROPERTY TABLES AND CHARTS (ENGLISH UNITS) 895
TABLE A–1E Molar mass, gas constant, and criticalpoint properties 896
TABLE A–2E Ideal-gas specific heats of various common gases 897
TABLE A–3E Properties of common liquids, solids, and foods 900
TABLE A–4E Saturated water—Temperature table 902
TABLE A–5E Saturated water—Pressure table 904
TABLE A–6E Superheated water 906
TABLE A–7E Compressed liquid water 910
TABLE A–8E Saturated ice–water vapor 911
FIGURE A–9E T-s diagram for water 912
FIGURE A–10E Mollier diagram for water 913
TABLE A–11E Saturated refrigerant-134a—Temperature table 914
TABLE A–12E Saturated refrigerant-134a—Pressure table 915
TABLE A–13E Superheated refrigerant-134a 916
FIGURE A–14E P-h diagram for refrigerant-134a 918
TABLE A–15E Properties of saturated water 919
TABLE A–16E Properties of saturated refrigerant-134a 920
TABLE A–17E Properties of saturated ammonia 921
TABLE A–18E Properties of saturated propane 922
TABLE A–19E Properties of liquids 923
TABLE A–20E Properties of liquid metals 924
TABLE A–21E Ideal-gas properties of air 925
TABLE A–22E Properties of air at 1 atm pressure 927
TABLE A–23E Properties of gases at 1 atm pressure 928
TABLE A–24E Properties of solid metals 930
TABLE A–25E Properties of solid nonmetals 932
Index 933
Nomenclature 947
Conversion Factors and Some Physical Constants 950