非稳态法测定杉木板材的水分扩散系数

Moisture diffusion coefficient of Cunninghamia lanceolata board with non-steady state conditions

用非稳态法在一定的实验条件下测定了人工林杉木Cunninghamia lanceolata板材的水分扩散系数，并且探讨了干燥介质温度、初含水率和纹理方向等对杉木板材水分扩散系数的影响。结果表明，干燥介质温度越高，扩散系数越大；初含水率越高，扩散系数越大，在纤维饱和点附近迭最大。当木材含水率在纤维饱和点以下时，杉木板材水分扩散系数都随着初含水率的增加而增大；当木材含水率在纤维饱和点以上时，扩散系数基本保持恒定；杉木板材的纵向水分扩散系数远大于横南水分扩散系数，其比值为5～7；杉木板材的径向水分扩散系数略大于弦向水分扩散系数，其比值为1．0～1．5。

Cunninghamia lanceolata （Chinese fir） board was tested systematically in non-steady state conditions to determine the moisture diffusion coefficient when the temperature of the drying medium, the initial moisturecontent （IMC）, and the texture direction varied. Results showed that the moisture diffusion coefficient increased with the increase of the drying medium temperature or IMC, reaching a maximum near the fiber saturation point （FSP）. When the moisture content was below the FSP, the moisture diffusion coefficient increased with the increase of the initial moisture content, but when the moisture content was above the FSP, the coefficient remained stable, The longitudinal diffusion coefficient was signifcantly larger than the radial and tangential diffusion coefficients, with ratios between 5 - 7, and the radial diffusion coefficient was clearly larger than the tangential diffusion coefficient with a ratio of about 1.0 - 1.5. [ Ch, 3 tab. 11 ref. ]