Governing equations for multiphase heat and mass transfer in hygroscopic porous media with applications to clothing materials
Abstract
Whitaker's theory of coupled heat and mass transfer through porous media was modified to include hygroscopic porous materials which can absorb liquid into the solid matrix. The system of equations described in this report should make it possible to evaluate the time-dependent transport properties of hygroscopic and non-hygroscopic clothing materials by including many important factors which are usually ignored in the analysis of heat and mass transfer through textile materials. The set of equations allows for the unsteady capillary wicking of sweat through fabric structure, condensation and evaporation of sweat within various layers of the clothing system, forced gas phase convection through the porous structure of a textile layer, and the swelling and shrinkage of fibers and yarns as they absorb/desorb liquid water and water vapor.
- Publication:
-
Final Report
- Pub Date:
- November 1994
- Bibcode:
- 1994army.rept.....G
- Keywords:
-
- Clothing;
- Evaporation;
- Forced Convection;
- Hygroscopicity;
- Porosity;
- Porous Materials;
- Shrinkage;
- Time Dependence;
- Transport Properties;
- Vapor Phases;
- Heat Transfer;
- Mass Transfer;
- Thermal Conductivity;
- Thermal Insulation;
- Water Vapor;
- Fluid Mechanics and Heat Transfer