Design with Constructal Theory

by Bejan, Adrian; Lorente, Sylvie

• ISBN13: 9780471998167
• ISBN10: 0471998168
• Edition: 1st
• Format: Hardcover
• Copyright: 2008-09-09
• Publisher: Wiley

Summary

Invented by Adrian Bejan, the constructal theory of global optimization under local constraints explains in a simple manner the shapes that arise in nature. The theory is used to understand, calculate, and ultimately generate the irregular designs found in nature (trees, lightning, river deltas, etc.) and incorporate these designs in human-made systems to optimize the function of the system. Now, for the first time in a book, Bejan explains the concepts and applications of his theory, beginning with the basics and building to more and more complex systems for better student understanding.

Author Biography

ADRIAN BEJAN, PhD, is the J. A. Jones Distinguished Professor of Mechanical Engineering at Duke University.

SYLVIE LORENTE, PhD, is Full Professor of Civil Engineering at the University of Toulouse, INSA, The Laboratory of Materials and Durability of Constructions.

Table of Contents

About the Authors	p. xi
Preface	p. xiii
List of Symbols	p. xvii
Flow Systems	p. 1
Constructal Law, Vascularization, and Svelteness	p. 1
Fluid Flow	p. 6
Internal Flow: Distributed Friction Losses	p. 7
Internal Flow: Local Losses	p. 11
External Flow	p. 18
Heat Transfer	p. 20
Conduction	p. 20
Convection	p. 24
References	p. 31
Problems	p. 31
Imperfection	p. 43
Evolution toward the Least Imperfect Possible	p. 43
Thermodynamics	p. 44
Closed Systems	p. 46
Open Systems	p. 51
Analysis of Engineering Components	p. 52
Heat Transfer Imperfection	p. 56
Fluid Flow Imperfection	p. 57
Other Imperfections	p. 59
Optimal Size of Heat Transfer Surface	p. 61
References	p. 62
Problems	p. 63
Simple Flow Configurations	p. 73
Flow Between Two Points	p. 73
Optimal Distribution of Imperfection	p. 73
Duct Cross Sections	p. 75
River Channel Cross-Sections	p. 78
Internal Spacings for Natural Convection	p. 81
Learn by Imagining the Competing Extremes	p. 81
Small Spacings	p. 84
Large Spacings	p. 85
Optimal Spacings	p. 86
Staggered Plates and Cylinders	p. 87
Internal Spacings for Forced Convection	p. 89
Small Spacings	p. 90
Large Spacings	p. 90
Optimal Spacings	p. 91
Staggered Plates, Cylinders, and Pin Fins	p. 92
Method of Intersecting the Asymptotes	p. 94
Fitting the Solid to the "Body" of the Flow	p. 96
Evolution of Technology: From Natural to Forced Convection	p. 98
References	p. 99
Problems	p. 101
Tree Networks for Fluid Flow	p. 111
Optimal Proportions: T- and Y-Shaped Constructs	p. 112
Optimal Sizes, Not Proportions	p. 119
Trees Between a Point and a Circle	p. 123
One Pairing Level	p. 124
Free Number of Pairing Levels	p. 127
Performance versus Freedom to Morph	p. 133
Minimal-Length Trees	p. 136
Minimal Lengths in a Plane	p. 137
Minimal Lengths in Three Dimensions	p. 139
Minimal Lengths on a Disc	p. 139
Strategies for Faster Design	p. 144
Miniaturization Requires Construction	p. 144
Optimal Trees versus Minimal-Length Trees	p. 145
75 Degree Angles	p. 149
Trees Between One Point and an Area	p. 149
Asymmetry	p. 156
Three-Dimensional Trees	p. 158
Loops, Junction Losses and Fractal-Like Trees	p. 161
References	p. 162
Problems	p. 164
Configurations for Heat Conduction	p. 171
Trees for Cooling a Disc-Shaped Body	p. 171
Elemental Volume	p. 173
Optimally Shaped Inserts	p. 177
One Branching Level	p. 178
Conduction Trees with Loops	p. 189
One Loop Size, One Branching Level	p. 190
Radial, One-Bifurcation and One-Loop Designs	p. 195
Two Loop Sizes, Two Branching Levels	p. 197
Trees at Micro and Nanoscales	p. 202
Evolution of Technology: From Forced Convection to Solid-Body Conduction	p. 206
References	p. 209
Problems	p. 210
Multiscale Configurations	p. 215
Distribution of Heat Sources Cooled by Natural Convection	p. 216
Distribution of Heat Sources Cooled by Forced Convection	p. 224
Multiscale Plates for Forced Convection	p. 229
Forcing the Entire Flow Volume to Work	p. 229
Heat Transfer	p. 232
Fluid Friction	p. 233
Heat Transfer Rate Density: The Smallest Scale	p. 234
Multiscale Plates and Spacings for Natural Convection	p. 235
Multiscale Cylinders in Crossflow	p. 238
Multiscale Droplets for Maximum Mass Transfer Density	p. 241
References	p. 245
Problems	p. 247
Multiobjective Configurations	p. 249
Thermal Resistance versus Pumping Power	p. 249
Elemental Volume with Convection	p. 250
Dendritic Heat Convection on a Disc	p. 257
Radial Flow Pattern	p. 258
One Level of Pairing	p. 265
Two Levels of Pairing	p. 267
Dendritic Heat Exchangers	p. 274
Geometry	p. 275
Fluid Flow	p. 277
Heat Transfer	p. 278
Radial Sheet Counterflow	p. 284
Tree Counterflow on a Disk	p. 286
Tree Counterflow on a Square	p. 289
Two-Objective Performance	p. 291
Constructal Heat Exchanger Technology	p. 294
Tree-Shaped Insulated Designs for Distribution of Hot Water	p. 295
Elemental String of Users	p. 295
Distribution of Pipe Radius	p. 297
Distribution of Insulation	p. 298
Users Distributed Uniformly over an Area	p. 301
Tree Network Generated by Repetitive Pairing	p. 307
One-by-One Tree Growth	p. 313
Complex Flow Structures Are Robust	p. 318
References	p. 325
Problems	p. 328
Vascularized Materials	p. 329
The Future Belongs to the Vascularized: Natural Design Rediscovered	p. 329
Line-to-Line Trees	p. 330
Counterflow of Line-to-Line Trees	p. 334
Self-Healing Materials	p. 343
Grids of Channels	p. 344
Multiple Scales, Loop Shapes, and Body Shapes	p. 352
Trees Matched Canopy to Canopy	p. 355
Diagonal and Orthogonal Channels	p. 362
Vascularization Fighting against Heating	p. 364
Vascularization Will Continue to Spread	p. 369
References	p. 371
Problems	p. 373
Configurations for Electrokinetic Mass Transfer	p. 381
Scale Analysis of Transfer of Species through a Porous System	p. 381
Model	p. 385
Migration through a Finite Porous Medium	p. 387
Ionic Extraction	p. 393
Constructal View of Electrokinetic Transfer	p. 396
Reactive Porous Media	p. 400
Optimization in Time	p. 401
Optimization in Space	p. 403
References	p. 405
Mechanical and Flow Structures Combined	p. 409
Optimal Flow of Stresses	p. 409
Cantilever Beams	p. 411
Insulating Wall with Air Cavities and Prescribed Strength	p. 416
Mechanical Structures Resistant to Thermal Attack	p. 424
Beam in Bending	p. 425
Maximization of Resistance to Sudden Heating	p. 427
Steel-Reinforced Concrete	p. 431
Vegetation	p. 442
Root Shape	p. 443
Trunk and Canopy Shapes	p. 446
Conical Trunks, Branches and Canopies	p. 449
Forest	p. 453
References	p. 458
Problems	p. 459
Quo Vadis Constructal Theory?	p. 467
The Thermodynamics of Systems with Configuration	p. 467
Two Ways to Flow Are Better than One	p. 470
Distributed Energy Systems	p. 473
Scaling Up	p. 482
Survival via Greater Performance, Svelteness and Territory	p. 483
Science as a Consructal Flow Architecture	p. 486
References	p. 488
Problems	p. 490
Appendix	p. 491
The Method of Scale Analysis	p. 491
Method of Undetermined Coefficients (Lagrange Multipliers)	p. 493
Variational Calculus	p. 494
Constants	p. 495
Conversion Factors	p. 496
Dimensionless Groups	p. 499
Nonmetallic Solids	p. 499
Metallic Solids	p. 503
Porous Materials	p. 507
Liquids	p. 508
Gases	p. 513
References	p. 516
Author Index	p. 519
Subject Index	p. 523
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