In order to design and automatically control various drying apparatuses, it is required to determine the simple approximated drying-rate equations and to obtain the rate parameters for the equations.
In a previous paper, we studied the drying-rate equations based on the drying-shell models. In the present paper, we postulated the drying-rate equations based on the uniform drying models, and calculated the rate parameters in the drying-rate equations of agar gel, carrot and cooked rice.
We studied the drying-rate equations which are postulated by the consideration of the drying-surface area S and by assuming that S may be correlated to the exponent of undisappeared water content (w-we). From the comparison of the calculated results, we concluded that S might be correlated to the exponent of (w-we), and that the order of the drying-rate equations which are postulated by assuming that S might be correlated to (w-we), is 0.5-1.0 for the used samples.
The calculated results of agar gel and carrot for the uniform drying model were similar to those for the drying-shell model described in a previous paper. For much results, former model is better than the latter one as the former is less intricated.