Modelling of Diffusion Process in Porous Bricks

Abstract: We consider drying process of bricks made of soil and cellulose mixture. The particle sizes of the soil are about 0.005 μm, which are considered to be clay. We apply a diffusion type equation to model the drying process. The model is based on macro modeling, where the particle and pore sizes are considered much smaller compared to the size of nails to measured the moisture content of the area inside the bricks. The model is a nonlinear diffusion equation where the diffusion rate depends on the moisture content. The solution is computed analytically applying a finite difference method for one and two dimensional cases. The simulation shows that the drying process of two dimensional case is slightly faster than of the one dimensional case. The cause is the diffusion to the side wall of two dimensional case where this wall is does not exist in one dimensional case.