Simulation of continuous flowgrain dryers

Resumo

Mathematical model and a computer program were developed to simulate the performance of continuous flow grain dryers. The mass and heat transfer processes were described by a system of four non-linear partial differential equations. This system was solved by the MacCormack method. Methods of Neumann and Matrix (considering the border conditions) were used for analysis of the convergence. The source-terms in these equations were defined by auxiliary semi-empirical equations, which were obtained by experimental data in the thin layer. In order to validate the model, the experiments were conducted in fixed bed. Simulations were made for various schemes of continuous flow dryers, including energy saving scheme with recycling the air for cooling and for drying of grain. To determine the initial conditions at the entrance to each section of dryer the iterative process was used. The computer simulations permitted to evaluate energy efficiency of each scheme, the duration of the drying process for geometry and initial moisture content of grains chosen.