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

Zaiton Mat Isa, Glenn Fulford, Neil Kelson


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.

  • K. Bullen, Insect control in stored grain, Technical report, DPIandF, Plant Science, Toowoomba, Queensland, 2007.
  • J. Canchun, D. W. Sun, and C. Cao, Computer simulation of temperature changes in a wheat storage bin, Journal of Stored Products Research, 37, 165--177, 2001. doi:10.1016/S0022-474X(00)00017-5
  • P. J. Collins, G. J. Daglish, M. K. Nayak, P. R. Ebert, D. Schlipalius, W. Chen, H. Pavic, T. M. Lambkin, R. Kopittke, and B. W. Bridgeman, Combating resistance to phosphine in Australia, Proc. Int. Conf. Controlled Atmosphere and Fumigation in Stored Products, Executive Printing Services, 593--607, 2001.
  • Comsol (2008). Comsol multiphysics user's guide.
  • P. W. Flinn and C. Reed, Effects of outside air temperature on movement of phosphine gas in concrete elevator bins, Proceedings of the International Conference on Controlled Atmosphere and Fumigation in Stored Products, 704--706, 2008.
  • Fluent, Ansys inc.
  • A. K. Singh and G. R. Thorpe, A solution procedure for three-dimensional free convective flow in peaked bulks of grain, Journal of Stored Products Research, 29, 221--235, 1993. doi:10.1016/0022-474X(93)90004-N
  • E. A. Smith, D. S. Jayas, and A. D. Ville, Modelling the flow of carbon dioxide through beds of cereal grains, Transport in Porous Media, 44, 123--144, 2001. doi:10.1023/A:1010760508392
  • E. A. Smith and D. S. Jayas, Modeling the movement of fumigant gas within grain beds, American Society of Agricultural Engineers, 44(3), 661--667, 2001.
  • S. Xu, D. S. Jayas, N. D. G. White, and W. E. Muir, Momentum-diffusive model for gas transfer in granular media, Journal of Stored Products Research, 38, 455--462, 2002. doi:10.1016/S0022-474X(01)00048-0

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