Nonisothermal moisture movement in wood

In order to study the effect of temperature gradient on moisture movement during high intensive drying such as microwave-vacuum drying, the authors measured the temperature and moisture content profiles in sealed wood whose opposite faces were subjected to temperature gradient for a short time.Then the absolute value of the ratio of the moisture content gradient to the temperature gradient(dM/dT) was calculated. The initial moisture content, temperature range and experimental period are all important factors affecting the experiment. The results indicated that moisture fluxed into the wood from the warm surface to the cold one even if opposite faces of the sealed wood assembly were exposed continuously to different but constant temperatures for a short period, the moisture content in cold surface was higher than that in the warm face, the moisture content gradient opposite to the temperature gradient was established, and the dM/dT is below 0.9/℃. Some factors, such as experimental time, temperature and initial moisture content in wood, had significant effects on dM/dT, which was found to increase with these factors。