Heat and moisture transfer and clothing thermal comfort

This thesis is concerned with a systematic study of the dynamic coupled heat and moisture transfer in porous textiles and its influences on the clothing dynamic thermal comfort. The research aims to establish a knowledge framework for design and development of textiles and clothing for thermal function and comfort by theoretical study and experimental investigation.; The research works have been carried out in the related knowledge areas such as neuropsychology, heat and moisture transfer in porous textiles, thermoregulation of human body and the perception of dynamic clothing thermal comfort. Significant results have been obtained as following: (1) The neuropsychological mechanisms of coolness and dampness perception to the touch of textiles was investigated by a series of psychophysical experiments and numerical simulations. The mechanisms is hypothesized as a process involving a series of interactive physical, neurophysiological and neuropsychological processes and was confirmed by the experimental findings. (2) New mathematical models were developed for the process of coupled heat and moisture transfer inside the multilayer isotropic and anistropic textile structures. Multiple coupled processes were considered, including the moisture vapor diffusion, heat transfer by conduction and radiation, phase change processes such as moisture sorption/desorption and evaporation/condensation, capillary liquid transfer as well as the influences from the fibers with different hygroscopicity and wetablity, water proof fabrics bonded at fabric surface and the contact situation of fabric layers. The models were validated by physical experiment with good accuracy and the further computational case studies have revealed complex interactions among different modes of moisture transport and the coupling effects between heat transfer and moisture transfer mechanisms. (3) A new one dimensional simulation model describing the dynamic heat and moisture exchange in Human-Clothing-Environment system has been developed by interfacing the isotropic transfer model with an improved Gagge's two-node model, which provides both dynamic physical status of clothing system and the dynamic thermal physiological of human body and the change of thermoregulatory effecter mechanisms. The model is validated with the published experimental results. Analysis of the simulation cases show that for textiles with different properties of heat and moisture transfer, even under the same environmental condition and physiological activity, the thermal regulative response can vary significantly. (4) A simulation of clothing thermal comfort with mathematical models and fuzzy logic for the perception of dynamic clothing thermal comfort was developed, as a practical integration of the models and simulation methodology developed in the research. The simulation system provide detailed dynamic status information in physical status of clothing system, physiological thermal status of human body with various thermoregulatory effecter mechanisms, neurophysiological responses of thermoreceptors, as well as the psychological temperature sensation, dampness sensation and dynamic thermal comfort. Good agreements were found between the predicted and experimental perceptual thermal sensations, dampness sensations and final dynamic thermal comfort ratings. (Abstract shortened by UMI.)...