基于木材构造分形的木材径向导热系数研究

基于分形理论通过试样木材的显微构造照片,采用盒维数法计算了其分形维数,由木材横纹的多孔结构特征和不同树种木材之间相对固定的分形维数(平均值约为1.495),建立了1个计算木材径向导热系数的分形模型。根据木材导热与导电规律的相似性,采用热阻模拟方法推导了径向导热系数的表达式,由木材孔隙率与分形维数的关系得到径向导热系数随分形维数变化的表达式。利用此关系式对试样木材径向导热系数进行计算,并与文献中的数据进行了比较;结果表明此分形模型可以对各种木材的径向导热系数进行方便而有效的计算.

RESEARCH WOOD RADIAL THERMAL CONDUCTIVITH BASED ON FRACTAL THEORY

Basing on the fractal theory,by using scanning electron microscope images of wood samples,their box-counting dimensions were calculated.From the cell structure of wood and different species of wood fractal dimension is relatively fixed(average about 1.495),a fractal model was proposed to calculate the effective thermal conductivity perpendicular to radial of wood.On the base of the fact that heat conduction of the material was similar to its electric conduction in terms of Ohm' resistance law,radial thermal...