微孔膜防水透湿织物热湿传递中织物表面凝结------外文翻译.doc

Condensation of Water Vapor on Waterproof Breathable Fabrics Condensation occurs when the local vapor pressure rises above the saturation vapor pressure at the local temperature in theory. A new measuring apparatus were made to obtain temperature and relative humidity simultaneously for the purpose of investigating the mechanism of condensation occurred on the fabrics. The experiment conducted at the standard condition of temperature of 20°C and relative humidity of 65%. The result obtained from experiment showed that condensation could occur under the situation closed to saturation line as the temperature on fabric may be lower than dew point of water vapor in the measuring box depending on the experiment conducted at an ambient environment temperature of 20°C. The range of fabrics studied showed that PTFE laminated fabrics except nylon gingham PTFE laminated fabric facilitates the loss of water vapor and therefore prevent condensation. It is necessary to develop studies from a wide range of fabrics, especially breathable fabrics and under bad experiment condition in order to develop fabrics, which could eliminate condensation, or transport water vapor through the fabric while remaining waterproof. Keywords: condensation ;waterproof breathable fabric. Introduction The human body through the process of metabolism is constantly generating thermal energy and moisture, which exchange through the textile layers with its environment .As perspiration escapes from the human body when the water vapor transfer from clothing is low .condensation defined as water droplet collected on the inner surface of the clothing may occur, provided that the local vapor pressure rises above the saturation vapor pressure at the local temperature. Keighley and Ruckman suggested from theory that the condensation occurring on the fabrics may be predicted if a saturation line and water vapor concentration line is utilized .Keighley developed a method that involved measurement of water vapor con