Finite element analysis of drying with application to cereal grains

A finite element procedure for two sets of non-linear coupled drying models for three-dimensional axisymmetric and two-dimensional problems are presented. The models consider temperature and moisture dependent material properties. The two different solution procedures used are the implicit two-level and the explicit three-level time stepping schemes. Application is made to drying of single soybean, barley and corn kernels. The simulation results from the heat and mass transfer models agree well with the available experimental results. Model one accounts for diffusion of moisture through vapour and liquid phases. Model two assumes that moisture diffuses to the outer boundaries of the kernel in the liquid form and that evaporation takes place only at the surface of the grain. In all simulations, temperature predictions using model one approached the equilibrium temperature faster than model two. The overall grain kernel temperature and moisture predictions from model two were better than model one. The choice of a model depends upon the type of application and availability of material properties.