Exploring the effects of the amplitude of variations in the intermittent drying with periodically changed relative humidity

Abstract

Intermittent drying is a modified drying method capable of energy saving and enhancing the quality of the dried product. The aim of the current research is to investigate the effect of the amplitude of air relative humidity intermittence on clay drying kinetics and induced stresses. A comprehensive mathematical model of the convective drying process has been presented. Simulation results show that reducing the amplitude of relative humidity changes enhances the effectiveness of intermittent drying on the maximum stress value. Increasing the relative humidity may increase the drying rate through increasing the wet bulb temperature. Increasing the amplitude causes a significant increase in drying time and stress fluctuation. The effect of the intermittence on the stress state varies from place to place. Intermittent drying may worsen/improve stress state. Dependence of the drying kinetics to the material properties and geometry makes it impossible to generalize the effectiveness of one scheme of intermittent drying to the other materials and geometries.