1980 年 36 巻 10 号 p. T427-T434
The effective thermal conductivity of the unidirectionally oriented polyester fiber assembly was measured by an experimental apparatus based on the steady comparative method using the glass plate as the standard sample. The results were discussed in terms of the theoretical analysis presented in the previous paper. The conclusions are as follows.
(1) The theoretical analysis based on the structural model predicts that at any mean sample temperature, the effective thermal conductivity falls with an increase of the volumetric ratio of a fiber assembly until it reaches a minimum value at a certain volumetric ratio. The conductivity rises with further increase of the ratio. The conductivity rises with the mean sample temperature, depending upon the temperature characteristic of the radiative heat transfer in the region of the low volumetric ratio or upon that of the conductive heat transfer in the region of the high volumetric ratio.
(2) The experimental results show that the effective thermal conductivity of the unidirectionally oriented polyester fiber assembly falls with the increase of the volumetric ratio, and reaches a constant value when the ratio exceeds 0.01. This tendency agrees with the theoretical prediction qualitatively. But in the region of low volumetric ratio, the experimental values are certainly larger than the theoretical ones. The experimentally observed temperature dependence of the thermal conductivity is well reproduced by the theory.