The transfer of heat and moisture through textiles is vital to the manufacture and design of clothing, technical and protective textiles. Continued advances in textile processing technology, the growth of manufactured nonwovens and the application of nanotechnology have resulted in a wealth of research in order to characterise the behaviour of these materials. Thermal and moisture transport in fibrous materials provides a comprehensive guide of the technological developments and scientific understanding in this area. The first section summarises the structure, geometry and stereology of fibrous materials. The fundamentals of wetting and its dynamics are also discussed. Part 2 analyses thermal and liquid interactions in textiles and offers insights into the thermodynamic behaviour of moisture as well as heat and moisture coupling. The book concludes with chapters on the human thermoregulatory system, interfacing between fibrous materials and the human body and innovative computer modelling simulations. Thermal and moisture transport in fibrous materials is an essential reference for all those involved in the textile industry, especially those concerned with the design and manufacture of technical textiles and protective clothing.
Author(s): N. Pan, P. Gibson
Year: 2006
Language: English
Pages: 632
1845690575......Page 1
Thermal and moisture transport in fibrous materials......Page 4
Contents......Page 6
Contributor contact details......Page 12
Introduction......Page 15
Part I Textile structure and moisture transport......Page 18
1.1 Geometrical characterization of single fibers......Page 20
1.2 Basic parameters for porous media......Page 21
1.3 Characterization of fibrous materials......Page 23
1.4 Mathematical descriptions of the anisotropy of a fibrous material......Page 28
1.5 Pore distribution in a fibrous material......Page 31
1.6 Tortuosity distributions in a fibrous material......Page 34
1.7 Structural analysis of fibrous materials with special fiber orientations......Page 36
1.8 Determination of the fiber orientation......Page 50
1.9 The packing problem......Page 54
1.10 References......Page 55
2.1 Introduction......Page 59
2.2 Basic stereological principles......Page 71
2.3 Stereology of a two-dimensional fibrous mass......Page 81
2.4 Stereology of a three-dimensional fibrous mass......Page 99
2.6 References......Page 115
3.1 Introduction......Page 119
3.2 Essentials of psychrometry (Skaar, 1988; Siau, 1995; Morton and Hearle, 1997)......Page 120
3.3 Moisture in a medium and the moisture sorption isotherm......Page 123
3.4 Wettability of different material types......Page 132
3.5 Mathematical description of moisture sorption isotherms......Page 136
3.6 References......Page 149
4.2 Wetting and wicking......Page 153
4.3 Adhesive forces and interactions across interfaces......Page 155
4.4 Surface tension, curvature, roughness and their effects on wetting phenomena......Page 160
4.5 Summary......Page 169
4.6 References......Page 170
5.2 Surface tension......Page 173
5.3 Curvature effect of surfaces......Page 175
5.4 Capillarity......Page 177
5.5 Surface roughness of solids......Page 184
5.6 Hysteresis effects......Page 193
5.7 Meniscus......Page 195
5.8 Instability of liquid flow......Page 197
5.9 Morphological transitions of liquid bodies in parallel fiber bundles......Page 200
5.11 References......Page 201
6.2 Fundamentals......Page 205
6.3 Complete wetting of curved surfaces......Page 210
6.4 Liquid spreading dynamics on a solid surface......Page 212
6.5 Rayleigh instability......Page 216
6.6 Lucas–Washburn theory and wetting of fibrous media......Page 220
6.7 Understanding wetting and liquid spreading......Page 231
6.8 References......Page 236
Part II Heat–moisture interactions in textile materials......Page 240
7.1 Introduction......Page 242
7.2 Thermal conduction analysis......Page 243
7.3 Effective thermal conductivity for fibrous materials......Page 250
7.4 Prediction of ETC by thermal resistance networks......Page 254
7.5 Structure of plain weave woven fabric composites and the corresponding unit cell......Page 258
7.6 Prediction of ETC by the volume averaging method......Page 266
7.7 The homogenization method......Page 276
7.8 Moisture diffusion......Page 279
7.9 Sensory contact thermal conduction of porous materials......Page 282
7.11 References......Page 283
8.1 Introduction......Page 288
8.2 Estimation of ventilation rates......Page 292
8.3 Heat and moisture transport modeling in clothing by ventilation......Page 300
8.4 Heat and moisture transport results of the periodic ventilation model......Page 315
8.5 Extension of model to real limb motion......Page 318
8.6 Nomenclature......Page 319
8.7 References......Page 322
9.2 Mass and energy transport equations......Page 325
9.3 Total thermal energy equation......Page 345
9.4 Thermodynamic relations......Page 353
9.5 Mass transport in the gas phase......Page 355
9.6 Gas phase convective transport......Page 357
9.7 Liquid phase convective transport......Page 358
9.8 Summary of modified transport equations......Page 361
9.9 Comparison with previously derived equations......Page 364
9.10 Conclusions......Page 368
9.11 Nomenclature......Page 369
9.12 References......Page 372
10.1 Introduction......Page 374
10.2 Discrete molecular dynamics......Page 381
10.3 Typical lattice gas automata......Page 395
10.4 Computer simulation of fluid flows through porous materials......Page 398
10.5 Sources of further information and advice......Page 412
10.6 References......Page 416
11.1 Introduction......Page 419
11.2 Modeling condensation/evaporation in thin clothing layers......Page 424
11.3 Modeling condensation/evaporation in a fibrous medium......Page 428
11.4 Effect of fabric physical properties on the condensation/evaporation process......Page 433
11.5 Modeling heating and moisture transfer in PCM fabrics......Page 435
11.6 Conclusions......Page 437
11.7 Nomenclature......Page 438
11.8 References......Page 439
12.1 Introduction......Page 441
12.2 Moisture regain and equilibrium relationships......Page 443
12.3 Sorption and condensation......Page 444
12.4 Mass and heat transport processes......Page 445
12.5 Modeling of coupled heat and moisture transport......Page 448
12.6 Consequences of interactions between heat and moisture......Page 451
12.7 References......Page 453
Part III Textile–body interactions and modelling issues......Page 454
13.2 Experimental investigations......Page 456
13.3 Theoretical models......Page 465
13.4 Numerical simulation......Page 473
13.5 Conclusions......Page 480
13.6 Nomenclature......Page 482
13.7 References......Page 483
14 Computer simulation of moisture transport in fibrous materials......Page 486
14.1 Introduction......Page 487
14.2 Auto-models......Page 495
14.3 Computer simulation......Page 526
14.4 Sources of further information and advice......Page 553
14.5 References......Page 555
15.1 Introduction......Page 559
15.2 Material modeling......Page 560
15.3 Material modeling example......Page 562
15.4 Modeling of fabric-covered cylinders......Page 563
15.5 Full-body modeling......Page 571
15.7 References......Page 575
16.1 Introduction......Page 577
16.2 Body–environment exchange......Page 578
16.3 Skin......Page 581
16.4 Heat exchange at the skin surface......Page 595
16.5 Moisture exchange at the skin surface......Page 601
16.6 Typical skin temperatures......Page 602
16.7 Sensation and comfort......Page 606
16.8 Modeling human thermal regulation and comfort......Page 613
16.9 References......Page 614
Index......Page 620
