Sep 30, 2015
1, wood and construction features
Different species of wood have different structures, its grain, pore size, and number, as well as on the pit membrane pore sizes vary greatly, so the ease with which water moves along the path above are different, namely wood drying rate is mainly internal. Due to loop holes hard hardwood (such as rosewood) catheters and filling in the pit, pit membrane micro-hole diameter is small, so the drying rate is significantly less than the diffuse porous hardwood; in the same species, density, water flow in capillary resistance, moisture diffusion path within the cell wall extension, it is difficult to dry.
2, wood thickness
Wood drying process can be considered as regular is along the direction of material thickness of one dimensional heat transfer and mass transfer process, increased thickness, long distance, heat and mass transfer resistance increases, the drying rate decreased significantly.
3, moisture content of wood
Below the fibre saturation point, with reduced water content, transverse diffusion coefficient of water absorption decreased, while the diffusion coefficient of water vapor in the cell cavities are increasing, due to drying of the proportion of water vapor diffusion in cell cavity less moisture low moisture diffusion path longer, so the lower the moisture content more difficult to dry.
4, wood, sapwood
Broad-leaved heartwood inclusions in the cells more coniferous tree pits mostly backwater in the heartwood, sapwood heartwood is difficult to dry.
5, wood grain
Ray to moisture conduction along radial moisture conductivity than wood along the strings to about 15%~20%, so usually quarter sawn lumber of strings fast-drying.