Numerical investigation into the aeration of grain silos

摘要

The aeration of grain silos provides a convenient means of controlling temperature andmoisture distribution in a silo. The moisture migration process is initiated by the presenceof temperature gradients which causes natural convective air movement within the grain.By being able to predict the moisture and temperature behaviour during the grain aerationprocess, the grower will be able to produce a more efficient aeration process thatminimises grain spoilage.The purpose of this project is to investigate the aeration characteristics of a grain silousing a Computational Fluid Dynamics package and develop an understanding of thecomplexities involved with the modelling of grain ecosystems with regard to airmovement, moisture migration and temperature distribution within the grain.More specifically, this project seeks to investigate numerically the effect of differentparameters of silos (size, shape, material, type or design and aeration rate) on thetemperature distribution in the stored grain, under a variety of seasonal conditions.The computational fluid dynamics software (Fluent 6.0) was used to investigate theseparameters and provided results in the form of contour plots (temperature and pressure)and velocity vector plots. The CFD package provides a strong basis for the analysis ofpacked beds. However, further attention needs to be paid to the reactions within theintergranular environment to allow the program to produce results of a higher degree ofaccuracy.