Advances in Heat Transfer (eBook)

Front Cover 1
Advances in Heat Transfer 2
Advances in Heat Transfer 4
Copyright 5
Contents 6
List of Contributors 8
Preface 10
On the Computational Modelling of Flow and Heat Transfer in In-Line Tube Banks 12
Greek Symbols 14
Acronyms 14
1. Introduction 15
2. Computational and Modelling Schemes 18
2.1 Discretization practices and boundary conditions 18
2.2 Turbulence modelling 21
3. Fully Developed Flow through In-Line Tube Banks 24
3.1 Domain-dependence and mesh-density issues for the LES treatment 24
3.2 Effects of pitch:diameter ratio 28
3.3 Effects of Reynolds number 31
3.4 Performance of URANS models for a square array for P/D=1.6 33
4. Modelling the Complete Experimental Assembly of Aiba et al. [13] 40
4.1 Scope of the study 40
4.2 Computed behaviour for the Test Section of Aiba et al. [13] 40
5. Thermal Streak Dispersion in a Quasi-Industrial Tube Bank 45
5.1 Rationale and scope 45
5.2 Streamwise fully developed flow 46
5.3 Computations of the complete industrial tube bank with thermal spike 48
6. Concluding Remarks 54
Acknowledgments 55
References 56
Developments in Radiation Heat Transfer: A Historical Perspective 58
Greek Letters 59
Subscripts 60
1. Introduction 60
2. Early Concepts of Light (Radiation) 61
3. The Nineteenth Century 62
4. Quantum Theory and Planck's Radiation Law 63
4.1 Planck's blackbody function 64
4.2 Limiting cases of the Planck's law 65
4.3 Stefan–Boltzmann law 66
5. Radiant Heat Exchange between the Surfaces of Solids 67
5.1 Radiation heat exchange in a gray, diffuse enclosure 69
5.2 Wavelength-dependent radiation properties 72
5.3 Radiation exchange between nonideal surfaces 72
5.4 Conjugate heat transfer: combined radiation with conduction and convection at boundaries 75
5.4.1 Combined conduction and radiation 75
5.4.2 Radiation combined with convection at boundaries 76
5.4.3 Radiation combined with conduction and convection 77
6. Radiative Transfer in a Participating Medium 77
6.1 Radiative transfer and radiant energy equation 78
6.2 Radiative transfer under radiative equilibrium 82
7. Interaction of Radiation with Conduction and Advection in Participating Media 84
7.1 Interaction of conduction with radiation 84
7.2 Combined conduction, advection and radiation 86
7.3 Interaction of radiation with turbulent flow 88
7.4 Interaction between combustion and radiation 89
8. Future Challenges 90
Acknowledgments 91
References 91
Convective Heat Transfer Enhancement: Mechanisms, Techniques, and Performance Evaluation 98
Nomenclature 
100 
Greek Alphabets 100
Subscripts 100
Abbreviations 101
1. Introduction 101
1.1 Background 101
1.2 Introduction to field synergy principle 103
1.3 Indicators of synergy 108
1.4 Techniques for enhancing single-phase convective heat transfer 112
1.5 Performance evaluation methods for enhancing techniques 122
2. Verifications of FSP 125
2.1 Verification of FSP deduction 1 125
2.2 Verification of FSP deduction 2 129
2.3 Verification of FSP for turbulent heat transfer 132
3. Contributions of FSP to the Development of Convective Heat Transfer Theory 134
3.1 FSP Revealing the condition for velocity to play a role in convective heat transfer 134
3.2 FSP revealing the upper limit of exponent m in the correlation of Nu~Rem 136
3.3 FSP explaining fundamental reasons of characteristics for some basic and enhanced heat transfer cases 136
3.3.1 Laminar fully developed heat transfer in tube: Nuq.NuT 136
3.3.2 Very high heat transfer coefficient at stagnation point of impinging jet 139
3.3.3 Role of fins 139
3.3.4 Heat transfer characteristics of flow across tube banks 139
3.3.5 Heat transfer characteristics of flow across tube bank with H-type fins 141
3.3.6 Heat transfer characteristics of flow across vortex generators 144
3.3.7 The role of nanoparticles in heat transfer enhancement 146
3.3.8 Enhancement of heat transfer in electronic devices 147
3.3.9 Enhancement of heat transfer in solar air heater 148
3.3.10 Improvement of thermal performance of pulse tube refrigerator 151
3.4 FSP guiding the developments of enhancing techniques with high efficiency 151
3.4.1 Design of slotted fin surface with “front sparse and rear dense” rule 151
3.4.2 Design of an alternating elliptical axis tube 158
3.4.3 Design of plain fin with radiantly arranged winglets around each tube 160
3.4.4 Improvement of bipolar channel for proton exchange membrane fuel cell 165
4. Performance Evaluation of Enhanced Structures 171
4.1 A unified log–log plot for performance evaluation 172
4.1.1 Basic equations for constructing performance evaluation plot 172
4.1.2 Composition of the NPEP 177
4.1.3 Contours of the working lines for the three constraints 179
4.2 Some typical applications examples of NPEP 179
4.2.1 Example of enhanced technique under identical pumping power constraint 179
4.2.2 Example of enhanced technique under identical pressure drop constraint 179
4.2.3 Example of enhanced technique under identical flow rate constraint 181
4.2.4 Comparison of enhanced technique with wavy channel as a reference 184
4.2.5 Comparison of helical baffle with segmental baffle of shell-side heat transfer in shell-and-tube heat exchangers 186
4.3 A comprehensive comparison study on techniques adopted in compact heat exchangers by the NPEP 187
5. Conclusions 188
Acknowledgments 191
References 191
Recent Analytical and Numerical Studies on Phase-Change Heat Transfer 198
1. Introduction 199
2. Surface Characteristics 201
2.1 Wettability 201
2.2 Roughness 202
3. Onset of Bubble Nucleation 204
3.1 Homogeneous nucleation 205
3.1.1 Gibbs free energy analysis 205
3.1.2 Availability analysis 206
3.2 Heterogeneous nucleation 208
3.2.1 Hsu's classical theory 209
3.2.2 Effects of contact angle 209
3.2.3 Effects of roughness 212
3.2.4 Effects of electric field 215
3.2.4.1 Homogeneous Nucleation 215
3.2.4.2 Heterogeneous Nucleation 218
4. Thermodynamic Analyses for Onset of Dropwise Condensation 219
4.1 Droplet condensation in pure vapor 219
4.2 Droplet condensation in moist air 220
5. Level-Set and VOF Simulations of Boiling and Condensation Heat Transfer 224
5.1 Boiling 224
5.2 Condensation 227
6. Lattice Boltzmann Simulations of Boiling Heat Transfer 231
6.1 The improved phase-change lattice Boltzmann model 231
6.1.1 The modified pseudo-potential LBM model for multiphase flows 232
6.1.2 Energy equation model 234
6.2 Bubble growth from a point heat source in pool boiling 235
6.3 Bubble growth from a point heat source in flow boiling 237
6.4 Bubble growth from multiple cavities in pool boiling 239
7. Lattice Boltzmann Simulations of Condensation Heat Transfer 243
7.1 Filmwise condensation 243
7.2 Dropwise condensation 246
8. CHF Models in Pool Boiling 249
8.1 Effects of contact angle 249
8.2 Effects of roughness 251
9. Concluding Remarks 255
Acknowledgments 255
References 256
Author Index 260
Subject Index 264