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An analytical model of internal transport characteristics of a textile material during drying using microwave heating is developed. The model is simplified for each period of drying (initial adjustment, liquid movement, constant rate, and falling rate) using existing experimental data and certain known characteristics of microwave heating. Solutions to these reduced modeling equations are obtained for the initial adjustment period and the constant rate period, which are the drying periods comprising the majority of the drying processes of most textile materials of interest. The analytical results are compared to the available experimental data, and a correlation is obtained in the prediction of drying rates, internal temperature profiles, and internal pressure distribution.

SUMMARY– Measurements of the moisture and temperature distributions were made during freeze‐drying beef at a pressure of 1 torr. The transient moisture distributions measured with gamma ray techniques indicate that the phase change region would have a thickness less than 3/16 in., that no drying takes place until the phase change region reaches a given position, and that no additional drying occurs after the phase change passes a given position. A careful study of the data showed that the drying rate was influenced by heat transfer through the frozen region to the phase change position.

Approximate solutions are obtained for the temperature distribution and rate of phase change for the transient one-dimensional solidification of a finite slab of a binary alloy. The alloy is selected to avoid the eutectic composition so that solidification takes place over a range of temperatures. The slab is initially superheated and has a uniform temperature distribution. Solidification occurs after one surface is cooled by convection while the other surface is insulated. Temperature distributions are determined analytically and experimentally and are in reasonably good agreement.