Mathematical Modeling & Numerical Simulation To Problems Of Heat And Mass Transfer In Textiles And Clothed Human Body

With the development of digital computer technology, the use of the CAD in the fashionable dress and textiles design has experienced greater and greater acceptance. The main purpose of the use CAD is to enhance the productivity and the agility in design process of the fashionable dress products. It can't satisfy with development function and comfortable products for the project to depend only on the traditional CAD system for fashionable dress design, because modern customers require individuation comfortability. However, in clothing industry, the function design CAD system is not well developed and used. One main reason is the complex heat and moisture transfer process and machanics property. Therefore, it is critical to develop sound scientific understanding on how heat and moisture can transfer in porous textiles. This work focuses on a theoretical investigation of how heat and mass can transfer in porous textile and how structures and material of clothing influence the human body by using the mathematical models developed recently.In the Chapter 1, the background of the discussed topics and realistic significance is expounded. Meanwhile, the research situation of the mechanisms of heat and mass transfer in porous textiles and human thermal regulatory model is concluded and summarized. Studying mechanisms of the heat and mass transfer in porous textile and developing the human thermal regulatory model are two main researching directions. Combined both, the human body/clothing/environment system can be simulated. The research method is determined.Chapter 2 reports a solution scheme for the coupled heat and moisture transfer equation. For the time domain, a mixed algorithm with precise time integration and finite difference is presented. For space domain, the finite element is applied. To avoid the unreasonable phenomena such as jump or vibratility in initial time step for solution thermal and moisture equations by finite element, the lumped mass heat capacity matrix and moisture capacity matrix are applied. The sorption or desorption rate of water by the fibers is considered as collection or source and a scheme of the predigested precise time integration is advanced.In the Chapter 3, a heat and moisture transfer model in macroscopic scale for fabric is developed. In the model the complex mechanisms, including conduction, convection and radiation are considered.In the Chapter 4, a multi-scale model is developed. The heat and mass transfer in pore of the textiles is considered as macroscopic scale, and the water vapor transfer in fiber is considered as microscopic scale. Water in fabrics is considered to be present in three forms: liquid water in the void space of inter-fibers, boundwater in the fibers, and vapor. It is assumed that the heat and mass transport mechanisms include movement of liquid water due to the capillarity and atmospheric pressure gradient, diffusion of vapor within inter-fibers due to the partial pressure gradient of vapor and total gas pressure gradient, diffusion of vapor into fiber, evaporation and condensation of water. The conclusion is that atmospheric pressure and its gradient have significant impact on heat and mass transport processes in hygroscopic porous materials.In the Chapter 5 and 6, based on the model of the Chapter 4, a 2-D model is developed for simulating the non-uniform environment. A new computational model is developed by integrating the Jones' multi-node model of human body with a model of dynamic coupled heat and moisture transfer in clothing. The model is able to provide a means to simulate the dynamic thermoregulatory responses of the clothed human body to windy environments.In the Chapter 7, Stolwijk's multi-node model is modified by considering the sweat accumulation on the skin surface and is applied to simulate the human physiological regulatory response. This human model is interfaced with a coupled heat and moisture model of clothing materials that takes into consideration the adsorption of water vapor in the fibers. Furthermore, a multi-layer clothing system is de...