18—the Movement of Vapour and Moisture During the Falling Rate Period of Drying of Thick Textile Materials

It is shown that during the falling rate period of drying, textile structures consist of a central core containing liquid water, the outer layers being dry. Vapour diffuses from this core at a rate governed by heat transmission to it. By balancing these two rates one can calculate the temperature within the body. It is further found that the position of the core surface is determined solely by the conditions within the core. From an analysis, the position of the core boundary is then accurately predicted. Knowing the temperature and position of the core boundary, the falling rate of drying curve can be predicted. The critical moisture content, however, cannot be predicted from the methods given.