木材横纹导热系数的类比法研究

分析导热与导电间某些属性的相似性 ,应用类比法推出导热系数具有导电系数的某些属性 ,可用导电系数类似的定义式定义导热系数 ,即木材导热系数等于木材单位长度单位截面的热阻的倒数。根据木材微观细胞形态 ,选用圆柱形模型推导木材横纹导热系数的理论计算式。应用该公式计算 2 0种木材的横纹导热系数 ,理论值的最大误差 14 1% ,平均误差 7% ,理论值与试验值较为吻合 ,为理论研究木材热学性质提供一种可适用的方法。

Study on Wood Thermal Conductivity in Transverse Direction by Analogism

Similarity of some properties between thermal conductivity and electricity conductivity was analyzed in this paper.Analogism reasoning was applied to infer that thermal conductivity had some properties of electricity conductivity. Therefore, thermal conductivity could be defined by definition formula similar to that of electricity conductivity, which thermal conductivity was the reciprocal of heat resistance per unit length and per unit cross section area of wood. The theoretical formula of wood thermal conductivity in transverse direction was inferred by cylinder model based on the cell structure of the wood. With the formula derived, the theoretical values of thermal conductivity in transverse direction for 20 tree species were calculated and comparison was also made to the experimental values under the same conditions. The results showed that the theoretical values of thermal conductivity is fairly identical to their experimental values, which the maximum error is 14.1% and mean error is less than 7%. The conclusion provided a feasible method to study thermal properties of wood theoretically.