ABSTRACT
Suppose that a wet nonhygroscopic porous material is being set in a hot airstream of constant temperature, humidity, and velocity. The water content w and the material temperature tm change with time during drying, as shown in Figure 10.1. The drying process consists of the following three periods: (I) preheating period, (II) constant drying-rate period, and (III) decreasing dryingrate period. Figure 10.2 shows the drying rate R in relation to the water content w. This curve is called the drying characteristic curve.
