Control of mechanical processes in drying. Theory and experiment

The paper deals with mechanical effects arising during drying of capillary-porous materials. The mechanistic model of drying appropriate for description of these effects and the experimental method for their detection are presented. Basically, the acoustic emission (AE) technique is shown as the effective tool for monitoring these effects and their control, in particular, for monitoring the stress development and control of drying processes towards their optimization with respect to drying time and product quality. The numerical solution of the mechanistic model illustrates the kinetics of drying and the stress development. The consistency of the theory and experiment is exemplified by convective drying of a cylindrically shaped samples made of kaolin and pinewood. The theoretical predictions validated by the experimental tests based on the AE technique offer a new tool for drying process optimization.