木材中の水分拡散係数の含水率依存性(<小特集>木質材料小特集)

概要

論文の詳細を見る
The purpose of this paper was to measure the change of moisture diffucion coefficient with drying and then to investigate the relationship between moisture content and diffusion coefficient. In this research, sdiscussions were limited to the isothermal moisture movenent, and also one dimensional diffusion in the direction of the board thickness (tangential direction) of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco.). During onventional kiln-dryiing, the inner moisture distribution change of the board can be non-destructively detected with the medical X-ray CT Scanner. Therefore, it can been continuously measured at the same part of the same section. This method was developed in this study to obtain more accurate moisture content in wood from CT images. As the noise of images was reduced by employing alternative techniques, the standard error achieved finally was 0.8% MC in the hygroscopic range. The diffusion coefficients were calculated directly from the moisture distribution change, by an appropriating differential equation for non-steady diffusion, as the driving force is MC. This research gave two interesting results. One is that, on the boundary layer between the lumber and the surrounding air, the moisture sorption did not rearch to an equilibrium state. Its MC was higher than EMC, which is being used generally. The maximum diference between them in the first stage of drying, was 6% MC, and in the last stage, it became 3〜5% MC at least. Another result was that the diffusion coefficient appeared constant independent of MC. However, the computer simulation of moisture distribution showed that a more appropriate correlatin seemed to be"The diffusion coefficient is dependent of MC, a cubic function with the maximum value of about 15% MC".
社団法人日本材料学会の論文
1989-07-15

木材中の水分拡散係数の含水率依存性(<小特集>木質材料小特集)

スポンサーリンク

概要

著者

関連論文

スポンサーリンク