Simulation of phosphine flow in vertical grain storage: a preliminary numerical study

Abstract

To fumigate grain stored in a silo, phosphine gas is distributed by a combination of diffusion and fan-forced advection. This initial study of the problem mainly focuses on the advection, numerically modelled as fluid flow in a porous medium. We find satisfactory agreement between the flow predictions of two Computational Fluid Dynamics packages, Comsol and Fluent. The flow predictions demonstrate that the highest velocity ($>0.1$\,m/s) occurs less than $0.2$\,m from the inlet and reduces drastically over one metre of silo height, with the flow elsewhere less than $0.002$\,m/s or $1$\% of the velocity injection. The flow predictions are examined to identify silo regions where phosphine dosage levels are likely to be too low for effective grain fumigation. References

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