抄録
The governing equations for isothermal drying of slabs of hygroscopic porous material are analyzed to develop a method for the approximate calculation of drying rate curves. Gradual decrease in surface moisture content is incorporated in the model by considering the effect of the desorption isotherm. The proposed method enables one to estimate drying rate curves for any conditions without solving drying equations when the dependence of moisture diffusivity and the desorption isotherm are given as functions of moisture content. Accuracy of the drying rates calculated by the method is examined by comparing with numerical solutions of the drying equations. When one of the internal and superficial mass transfer resistances is dominant, approximate drying rate curves show very good agreement with numerical solutions. When both resistances are comparable, the method underestimates drying rates with errors of less than 6%.
