Modelling of the drag force of agricultural seeds applied to the discrete element method

摘要

Improvements in design and performance of post-harvesting equipment, such as grain dryers, cleaning machines, silos, bucket elevators and conveyors, depend on better knowledge of the physical properties and dynamic behaviour of seeds. In this work, experimental data regarding form, size, orientation, and terminal velocity of seeds of soya, oat and maize were obtained using image processing and fluidised bed methods. The discrete element method (DEM) has been applied for the simulation of different processes involving agricultural seeds, but aerodynamic properties, such as drag force, are not always correctly considered. In this work, a clump-based drag engine model for the Yade DEM simulation tool was developed, and DEM simulations of the seeds free fall were performed. The comparison between the simulation results and the experimental data shows that the developed method is accurate, with its accuracy dependent on how well the modelled seed geometry can be approximated by an ellipsoid. (C) 2018 IAgrE. Published by Elsevier Ltd. All rights reserved.