A receding evaporative front model for the drying characteristics of a flat plate II: stress and strain development

Abstract

An analysis that captures the receding drying front is presented for the stress and strain produced during a three-stage drying process of an elastic flat plate with a fixed base. In the first stage (saturated stage), the body is fully saturated and pressure-driven flow prevails according to Darcy\'s Law. During the second stage (partially saturated stage), the evaporative front recedes through the material and divides the material into saturated and unsaturated zones; the equations for saturated flow apply to the saturated region, while moisture transport in the unsaturated region is by diffusion. During the third stage (fully unsaturated stage), the body is entirely unsaturated and moisture is lost by diffusion only. The position of the evaporative front is updated using the maximum capillary tension at the interior of the evaporative front as it recedes through the material. The stress on the solid matrix increases in proportion to the thickness of the plate and the rate of evaporation, and in inverse proportion to the permeability. The maximum stress occurs at the drying surface of the plate.

Keywords: drying, stress, strain, evaporative front, flat plate

Global Journal of Engineering Research Vol.4 (1&2) 2005: 39-48