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Radix CFD Team Recognized For Their Work On Seed Clustering In Air Seeders

May 30, 2017

Two of our team members, Chris Johnston and Mohsen Bayati, will be speaking at this years CFD Society of Canada's 25th Annual Conference held at the University of Windsor. The event will take place between June 18th and 20th, 2017. Chris and Mohsen wrote a paper on using CFD simulation and modeling to improve an air seeder's seed distribution. See the excerpt below:

Agricultural air seeders typically have uneven distribution of seeds from their outlets, leading to irregular planting patterns and inefficient farming. When larger seeds are used, a clustering effect can also occur where seeds emerge, not in steady streams, but in clustered groups. This work investigates the causes of these effects with a CFD-DEM approach to improve future air seeder design. Two modelling approaches are attempted.

air seeder

In the first approach, small particles based on wheat seeds are modelled with one-way coupling to validate the numerical models and spatial discretization based on experimental results for the outlet distribution. In the second approach, the Immersed Boundary (IB) method as modified by Hager (2014) is used in twoway coupling to capture the effect of larger particles (based on chickpeas) on the flow.

The first method finds a coefficient of variation (CV) between the 11 different outlets of 12.5%, which is within the accepted range of typical air seeder performance, and matches the reported number by the industry. For the second approach, the concept of a “time CV” is introduced to describe the relative amount of clustering in larger seeds based.

air seeder steady flow

The clustering effect is found to be largely due to obstructions in the flow causing the seeds to drop into Geldart’s “spouted bed” fluidization regime (Geldart, 1973), resulting in periodic bursts of seeds after localized pressure build-up. Results of the simulations were compared to experimental data, and are in good agreement.

Agricultural air seeders typically have uneven distribution of seeds from their outlets, leading to irregular planting patterns and inefficient farming. When larger seeds are used, a clustering effect can also occur where seeds emerge, not in steady streams, but in clustered groups. This work investigates the causes of these effects with a CFD-DEM approach to improve future air seeder design. Two modelling approaches are attempted.

air seeder unit

Chris and Mohsen will be at the CFD Conference between June 18th and 20th of 2017. Make sure to head down to the University of Windsor and see them speak or catch up with them to discuss their research!