Analytic modelling of drying of porous materials

Abstract

Recent experimental data by Pel has revealed the spatial and temporal structure of the moisture content during the drying process within building materials such as bricks. A simple model of the water motion is presented, guided by the observed behaviour, which allows for non-linear diffusion within the brick and a mass transfer coefficient to represent the moisture transfer between the external air current over the brick. An approximate analytic solution to the model is developed, giving the moisture profiles evolving with time. This gives insight into the different phases of the process, which consists of a rapid decrease in the moisture content in a relatively uniform manner, followed by t..