多孔介质等效导热系数的较高精度通用计算式

A NEW FORMULA FOR CALCULATING EFFECTIVE THERMAL CONDUCTIVITY OF POROUS MEDIA WITH COMPARATIVELY HIGH PRECISION

一、概述 多孔介质的材料在建材和隔热技术中应用很广,用理论方法计算其导热系数并指导材料改性的设计是十分有意义的。已被广泛使用的Eucken,Loeb和Russell等算式仍然有缺点,不能反映在某些参数改变时的差别。本文根据最小热阻力法则,导出了包含气孔内气体传导和辐射项的多孔体的等效导热系数λ_e的计算式。它含有8种参数,由λ_(et)、λ_(eb)及加权因子P_λ组成。

The formula obtained in this study consists of the minimum λst,.the. maxmum λsb and the weight factor Pλ which contains 8 parameters. It is compared with Eucken's, Russell's and Loeb's formulas and some experimental data in references, the formula has more applicability and higher accuracy than them.