玻璃纤维保温纸导热系数的理论计算与实验研究

Theoretical Calculation and Experimental Study of Thermal Conductivity Coefficiency of Glass Fiber Heat Insulation Paper

建立玻璃纤维均匀排列的导热模型对玻璃纤维保温纸的等效导热系数进行预测。根据分形维数代表保温材料内部纤维排列的杂乱程度,通过实际材料与理论模型分形维数的比值来对保温材料进行纤维排列不均匀度的修正。依据等效热阻法,确立基于修正系数基础上的导热系数计算通用公式。通过对在不同玻璃纤维直径和不同孔隙率条件下计算结果的分析,讨论玻璃纤维直径和材料孔隙率对保温纸导热系数的影响,在此基础上确立基于材料孔隙率的导热系数近似简易预测公式。文中导热模型推导出的通用公式与预测公式的计算结果与实验结果吻合较好,所以可以用该计算模型来预测材料的导热系数。

A thermal conductivity model of uniformly arranged glass fibers was proposed to predict the effective thermal conductivity coeffi- ciency of glass fiber heat insulation paper. Due to the fractal dimension stands for the mixed and disorderly degree of the internal fiber arrays of heat insulation materials, the non-uniformity of fiber distribution is amended by using the fractal dimension ratio of factual material and the model. Based on the correction factor, universal expression of the effective thermal conductivity was developed according to the equivalent thermal resistance method. Based on the analysis of the calculation results under the conditions of the different glass fiber diameter and poros- ity, the impact of glass fiber diameter and material porosity on the thermal conductivity of the insulation paper was discussed, and the approx- imate simple prediction equation of the thermal conductivity coefficiency was established. The calculation results of the universal expression derived from the thermal conductivity model and the prediction expression accord well with that of experiments, so the model can effectively predict the conductivity coefficiency of the heat insulation paper.