Discrete Element Method (DEM) simulation of corn grain flow in commercial screw auger
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Screw augers are primary grain conveying equipment. Quantitative prediction of screw auger performance requires better understanding and measurement of bulk particle-to-particle and particle-to-geometry interactions. Discrete Element Modeling (DEM) has the potential to simulate particle dynamics and flow within a screw auger, and thus to provide simulation-based guidance for screw auger design and operational parameters. The objective of this study was to calibrate DEM corn modeling using Angle of Repose (AOR) and to simulate DEM corn flow in a commercial screw auger. Experimental data was collected to characterize harvested corn, angle of repose, and grain flow from a screw auger.
Corn particle was modeled using four types of DEM spheres represented as 1-sphere and clumped spheres 2-sphere, 5-sphere and 13-sphere matching to a physically measured corn shape with equivalent geometrical diameter, 2D axial dimension, 3D axial dimension, and parameterized CAD dimensions, respectively. For each DEM corn shape approximation, virtual Design Of Experiments (DOE) with four DEM material interaction coefficients as independent parameters and reproducing AOR test initial conditions were developed in EDEM to simulate AOR grain flow behavior. AOR values from quasi-static corn flow on flat plate were measured in lab and compared with the DOE DEM simulation. The DEM corn with 2-sphere and the material interaction coefficients showed good prediction to the experimental corn AOR test with minimum corn height test and DEM prediction difference of Mean Square Error (MSE) (5.31 mm2) compared to 1-sphere, 5-sphere and 13-spheres. With computationally-inexpensive shape and calibrated DEM material properties from AOR, screw auger DEM simulation of corn model was performed to predict mass flow rate. Results from DEM, analytical solutions, and experimental data on mass flow rate were also compared.
This paper is from 2016 ASABE Annual International Meeting, Paper No. 162462358, pages 1-14 (doi: 10.13031/aim.20162462358). St. Joseph, Mich.: ASABE. Posted with permission.