| The traditional way of keeping warm cannot control the temperature actively,the effect of keeping warm is not good,even the heavy clothes restrict activities.Also,It can not meet the thermal requirements of people suffering from diseases(such as palace cold,rheumatism,arthritis,etc.)or people susceptible to cold constitution.Therefore,it is of great practical significance to introduce auxiliary heating and temperature control elements in textiles and develop heating textiles with active heat source.This project selects a suitable conductive heating material and embeds it into woven fabric through warp and weft interweaving to prepare an electrically heated fabric.Then,the electrical heating performance and heating uniformity of the electrically heated fabric are studied.This project provides a certain reference for the comfort index of electric heating textiles,and provides a new idea for the development of electric heating textiles for enterprises.The specific research content is as follows:1.The size,resistance and heating effect of five kinds of conductive heating materials are analyzed,and suitable conductive heating materials are selected according to the actual heating effect and weaving property.2.Stainless steel composite heating yarn is selected as the research object to participate in the weaving of woven fabric by adding yarn.Electric heating machine fabric was prepared based on orthogonal test.3.In order to eliminate the contingency error caused by the preparation of electrically heated fabrics with one-dimensional heating elements,the test method of heating uniformity was optimized.4.The heating characteristics of the electric heating fabric were tested to explore the significant influence of various process parameters on the electric heating properties and heating uniformity of the electric heating fabric.5.The subjective evaluation test evaluates the fabric thermal sensation and heat uniformity on an interval scale and uses entropy-weighted TOPSIS synthesis analysis to arrive at the optimal term.Through the analysis and research of the above series of experiments,the following conclusions are drawn: acrylic metal blended yarn,silver coated fiber,yarn coated copper and yarn coated manganese copper,the above can conduct electricity,but cannot generate heat.Copper bare wire has good joule thermal effect,but the bare wire is slender and has poor resistance stability.Carbon fiber electric heating is good but not good for weaving on jacquard machine.Stainless steel fibers are selected for the preparation of electric heating woven fabrics for their excellent Joule thermal properties and weaving property.In the pre-experiment,it was found that the instantaneous temperature distribution on the surface of the double-layer fabric was more uniform than that of the single-layer fabric,and the higher temperature could be obtained by inserting the fiber heating yarn at equal intervals,and the temperature uniformity coefficient was also higher,the worse the uniformity.The heating uniformity test scheme was optimized about extending to 25 points,49 points,81 points,121 points and 169 points on the basis of the nine-grid point method.The temperature uniformity coefficient first increased with the increase of points and then gradually stabilized.There was no obvious growth trend after 81 points,so this scheme was chosen as a credible evenness evaluation scheme in this study.Based on the nine samples obtained from the orthogonal test,the extreme difference analysis was conducted: for the heat generation performance,the significance ranking of the factors was yarn distribution ratio > weft density > fabric structure,and the optimal condition was yarn distribution ratio 1:3,weft density 105 roots/10 cm,warp weight 1/7(i.e.,the optimal term was sample H3),and the electrically heated fabric prepared under this condition had the maximum heat generation power density.The optimal condition is yarn distribution ratio 1:5,weft density 65 / 10 cm,and warp weight1/3,and the electric heated fabric prepared under this condition has the best heat uniformity.In the objective test,H5 showed the best uniformity of heating.The reason for the slight deviation is that some subjective feelings may involve multiple dimensions,such as temperature or feel,but the psychological scale usually measures only one dimension.Entropy-weighted TOPSIS analysis of the subjective and objective evaluation indicators,resulting in nine samples ranking results: H3>H2>H6>H1>H9>H5>H4>H8>H7.The optimal item H3 under the comprehensive evaluation,but a long exposure to the heat source of 45 ℃,although it does not feel hot,but nociceptive nerve numbness after a long contact time,will cause lowtemperature burns.Therefore,we choose the sample H4,which can be controlled stably at about45℃ and has good subjective and objective comprehensive evaluation,and the maximum equilibrium temperature is 45.24℃. |
PDF Full Text Request