ABSTRACT
Tufted Textile Material ................................................. 244 11.5 Heat Flow and Clothing Comfort ............................................... 250
11.5.1 Introduction and Background ....................................... 250 11.5.2 Effective Thermal Conductivity ................................... 260 11.5.3 Transport Phenomena for Sweat .................................. 264 11.5.4 Factors Influencing the Comfort Associated with
Wearing Fabrics ............................................................ 266 11.5.5 Interaction of Moisture with Fabrics ............................ 266 11.5.6 Moisture Transfer in Textiles ....................................... 268 11.5.7 Water Vapor Sorption Mechanism in Fabrics ............... 270 11.5.8 Modeling ...................................................................... 274
11.6 Appendix .................................................................................... 279
11.6.1 Heat Transfer .............................................................. 279 11.6.2 Mass Transfer ............................................................. 279 11.6.3 Drying of Textiles ....................................................... 279 11.6.4 Steady State Heat Transfer ......................................... 280 11.6.5 Convective Heat-transfer Coefficient ......................... 280 11.6.6 Dimensionless Numbers in Convective Heat Transfer 281 11.6.7 Radiation Heat Transfer .............................................. 282 11.6.8 Combining Radiation and Convection Heat Transfer 282 11.6.9 Conductive Heat Transfer ........................................... 283 11.6.10 General Concepts ........................................................ 283 11.6.11 Drying of Porous Nanostructure Fabrics .................... 286 11.6.12 Convection Heat Flow in Porous Media .................... 288 11.6.13 Conduction Heat Flow in Porous Materials ............... 291 11.6.14 Radiation Heat Flow in Porous Solids ........................ 292 11.6.15 Porosity and Pore Size Distribution in a Body ........... 295 11.6.16 Pore-size Distribution in Porous Structure ................. 298 11.6.17 Basic Flow Relations in Porous Body ........................ 303 11.6.18 Transport Mechanisms in Porous Media .................... 304
Keywords .............................................................................................. 309 References ............................................................................................. 310
11.1 INTRODUCTION
Drying of wet porous media is coupled in a complicated way. The structure of the solid matrix varies widely in shape. There is, in general, a distribution of void sizes, and the structures may also be locally irregular. Energy transport in such a medium occurs by conduction in all of the phases. Mass transport occurs within voids of the medium. In an unsaturated state these voids are partially filled with a liquid, whereas the rest of the voids contain some gas. It is a common misapprehension that non-hygroscopic fibers (i.e., those of low intrinsic for moisture vapor) will automatically produce a hydrophobic fabric. The major significance of the fine geometry of a textile structure in contributing to resistance to water penetration can be stated in the following manner.
