衣服の保温性能評価指標としての布の熱移動特性  [in Japanese] Heat Transfer Characteristics of Cloth for Thermal Function of Clothes  [in Japanese]

Heat transfer coefficients of cloth for various clothing materials have been measured by experiments of heat transfer from hot water within a rotating glass bottle into surrounding air, where one sheet or two sheets of cloth were wrapped around the bottle. Heat transfer resistance of one sheet of cloth was determined by calculating the difference between the overall heat transfer resistances when two sheets of cloth were used and those when one sheet of cloth were used. The heat transfer coefficient of cloth having the same thermal conductivity of fiber and the same volumetric fraction of fiber is in reverse proportion to cloth thickness for woven cloth. Cotton or hemp give remarkably larger heat transfer coefficients than wool, silk or polyester due to the larger thermal conductivity within them. It was shown that the heat transfer coefficient of cloth can be estimated by the weighted mean of values evaluated by two models: the first model having cloth construction with a fiber arrangement perpen-dicular to the cloth surface which gives the largest heat transfer coefficient and the second one having a fiber arrangement parallel to the cloth surface which gives the smallest heat transfer coefficient. The observed value of the heat transfer coefficient of cloth was also compared with the value estimated by the model from available literature.