非稳态纺织复合保温材料导热性能的研究

发布时间：2018-10-26 18:40

【摘要】：随着科技的发展,各种高性能纤维及复合技术相继出现,纺织复合保温材料的应用领域已经从服用拓展到了各类工程领域。户外使用的纺织复合保温材料,内部的传热通常处于非稳态传热过程,目前纺织复合保温材料导热性能的测试大都采用稳态测试法,并不能真实反映材料在户外使用时的内部导热情况。本课题以农用纺织复合保温材料作为研究对象,通过搭建的非稳态测试平台、采用MATLAB数值解析程序,测试分析研究了环境因素及结构因素对材料的导热性能的影响。基于非稳态无限大平板导热模型推导出计算热导率的温度时间函数,通过MATLAB编程拟合计算得到材料热导率,此程序可以简单快捷处理内部温度随时间变化的数据。搭建了非稳态测试装置,并进行了准确度测试分析,通过与稳态测试分析比较发现,采用非稳态测试方法得到的热导率离散度低,可重复性强。系统的研究了环境因素对导热性能的影响。环境湿度增大会引起材料的含湿量增大从而加快热传导性能:环境温度升高,材料的导热性能总体呈现增加的趋势,但变化趋势并不是很大;初始温度在小范围内波动时,热导率的变化不大,当初始温度变化较大时,热导率有明显增大的趋势。测试分析研究了材料结构参数对导热性能的影响。采用涤纶复合聚乙烯涂层膜作为表层覆盖材料时,材料的保温隔热性能最好;热导率随着孔隙率的增大而减小,当孔隙率含量在85%时,热导率达到最小值;随着回潮率的增加,材料的导热系数增加;对变密度结构的纺织复合保温材料,选用外层密度较大而内部密度较小的结构时,其热导率最小。
[Abstract]:With the development of science and technology, various kinds of high performance fiber and composite technology have appeared one after another. The application field of textile composite insulation material has been expanded from wearing to various engineering fields. The heat transfer inside the textile composite insulation materials used outdoors is usually in the process of unsteady heat transfer. At present, the thermal conductivity of textile composite thermal insulation materials is mostly tested by the steady-state test method. It does not really reflect the internal heat conduction of the material in outdoor use. In this paper, the influence of environmental factors and structural factors on the thermal conductivity of agricultural textile composite thermal insulation materials is studied by using the MATLAB numerical analysis program and the unsteady test platform. Based on the unsteady infinite plate heat conduction model, the temperature time function for calculating thermal conductivity is derived, and the material thermal conductivity is calculated by MATLAB programming. This program can deal with the data of internal temperature with time quickly and simply. The unsteady-state testing device is built and the accuracy analysis is carried out. The results show that the thermal conductivity dispersion is low and the repeatability is strong by using the unsteady-state test method compared with the steady-state test analysis. The influence of environmental factors on thermal conductivity was studied systematically. The increase of environmental humidity will lead to the increase of moisture content of the material, thus speeding up the thermal conductivity: the thermal conductivity of the material increases with the increase of ambient temperature, but the change trend is not very large; When the initial temperature fluctuates in a small range, the thermal conductivity does not change much, but when the initial temperature changes greatly, the thermal conductivity increases obviously. The influence of material structure parameters on thermal conductivity was studied. When polyester composite polyethylene coating film is used as the coating material, the thermal conductivity is the best, and the thermal conductivity decreases with the increase of porosity, and the thermal conductivity reaches the minimum when the porosity content is 85. With the increase of moisture regain, the thermal conductivity of the material increases, and the thermal conductivity of the textile composite thermal insulation material with variable density structure is the lowest when the structure with higher outer density and lower internal density is selected.
【学位授予单位】：西安工程大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB33

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