Research On Testing Method Of Fabric Heat Transmitting Property

The thermal property of textiles is an important parameter related to human body comfort, and extensive research work has been done in this area. Many studies of thermal properties, which carried out so far are mainly concentrated on the static state, but few researches on the dynamic state thermal properties have been done. In this article, a design scheme of heat transmitting property testing equipment under heated condition is proposed from converse thought, which based on the former researches and considered the characteristics of the plat-plate warmth retention testing. So the dynamic method of fabric heat transmitting properties is studied systematically in this thesis. The main contents are as follows:1. Development of apparatus to test dynamic heat transmitting properties of fabrics. In this apparatus, the design program, testing basic frame and principal, acquired the experiment data by compute, determined the heater heat flux and sensors calibration are discussed. Through experiment proof, the apparatus meets with the design requests.2. The evaluation indexes, which sign the testing results, are put forward,the indices include the difference of calefactive ratio, the heat insulationratio, effective thermal conductivity, compound thermal resistance and response time. These indexes describe the fabric's thermal properties during the heated process. The heat insulation ratio preferably manifests fabric's insulation property; the difference of calefactive ratio describes dynamic conditions average calefactive case; effective thermal conductivity and compound thermal resistance are mainly considering the wholly testing characteristics and describing the compound thermal property; the response time expresses the time of step response duringdynamic testing process.3. Dynamic heat transmitting properties of fabrics and warmth retention testing methods have been developed; many different textile materials are used for actual test, and the data are analyzed, illustrated, and compared. Through regression analysis, the results show: The evaluation indexes acquired by dynamic method have some definite correlation, demonstrating between the indexes there is intrinsic dependence. There exist much difference between dynamic and static heat property, but the insulation ratio and the warmth retention ratio also have some correlation when considering the fabric's parameter. The dynamic indexes and fabric thickness have exponential relationship, but the static indexes and fabric thickness have linear relationship.4. Moreover, the characteristics of testing curve are discussed, and analyzed the heat property theoretically. The fabric's thermal conductivity is further analyzed through effective thermal conductivity; the result shows fabric's thermal conductivity has correlation to the heat flux through the fabric and the temperature difference. The dynamic and static methods are also compared, and it proves the dynamic testing apparatus is feasible.