Computational Fluid Dynamics Analysis of Phosphine Gas Distribution for Effective Fumigation in Grain-Filled Barrel

<sc>Abstract. </sc>In the food distribution supply chain, storage containers play a significant role in distributing grains year-round to fight the food crisis. However, a significant amount of grain is wasted due to insect infestation in the storage and shipping process. Phosphine (PH₃) fumigant, distributed using solid or gaseous form, is studied here for its effectiveness in treating grain and grain-based commodities to control pests and maintain grain quality. Effective fumigation requires maintaining a lethal concentration of PH₃ (usually above 200 ppm) for an extended period of time. Several key factors influence how phosphine gas disperses including domain size, headspace, temperature variations, the sorption characteristics of grain, and container leakages. This study uses computational fluid dynamics (CFD) to investigate the distribution of phosphine in grain-filled barrels containing wheat. The current CFD model is based on a simplified 2D barrel. Our CFD analysis shows how the domain size and headspace affect phosphine gas distribution in the grain barrel. The analysis also finds that a reasonable distribution of phosphine gas in the barrel allows its concentration to remain above 200 ppm. Future work involves exploring other factors through numerical analysis and developing a more realistic 3D model of the barrel.