Modelling the microclimate in a conical bottomed circular grain silo

A three-dimensional mathematical model for predicting the behaviour of microclimate\ud in the stored grain silo is presented. This analysis is implemented by calculating the air\ud pressure field within an aerated conical bottomed circular silo, to continuing prediction\ud the velocity field. The obtaining results are used to compute the simultaneous heat and\ud mass transfer processes that occur in non-aerated and aerated grain silos. The\ud conservation equations of momentum, mass and energy are employed in this study. The\ud numerical scheme is based on applying a mapping technique with an algebraic grid\ud generation method, to discretise the governing equations in the arbitrary geometries that\ud describe the grain stores.\ud The finite different solution of the governing equations are obtained by using\ud Alternating Direction Implicit method, Thomas algorithm and explicit method. The\ud numerical experiments have been performed to investigate the effects of the nonuniform\ud grid size, time step, duct shape and placement. Results in graphical form are\ud presented for the pressure, velocity, temperature, moisture content, absolute humidity,\ud wet bulb temperature, dry matter loss, seed viability and pesticide decay.\ud Significantly, a novel configuration of an annular aeration duct and a traditional linear\ud aeration duct in farm silos have been investigated. It was found that the annular\ud aeration system provides uniform airflow results in better protection of the stored grains\ud than in the linear aeration system, in that the beneficial grain quality indices remain\ud high, and the rate of growth of insect population is retarded.\ud An outcome of the research has been improved the designs of commercially available\ud grain silos