Mixing enhancement of wheat granules in a hopper bottom lab-scale mixer using discrete element simulations

In the agricultural industry, the conservation of wheat grains in silos after stocking is a hard task. This is because when stocking a large crop, hot aeration from the bottom of the silo is not sufficient to preserve the crop and avoid losses due to the manifestation of moisture between grains and grains-wall. As a concern, engineers, as well as inspectors, challenged day-to-day issues whenever packing such granular material. A screw could be a good solution to improve the dryness of the particles and mix the bed material in case of stocking different types of grains. Mainly, the complexity does emanate from the model used to predict accurately the mixing performance. Emerging generation of simulation codes using the discrete element method (e.g., EDEM®, LIGGGHTS, etc.) have brought an intact solution to the problem of particulate flow and particles inhomogeneity. The present work has sought to develop predictive models for average mixing index and particles velocity distribution assessments in mixing of wheat granules in a small-scaled hopper base screw mixer. A screw-mated-horizontal-ploughs has been utilized to improve the agitation of grains rather than a simple screw. 1, 2 and 4 mated ploughs to the screw axle has been used, also the tilt angle of the 4 mated ploughs case has been varied as follows; 20°, 45° and 70° then evaluated. Next, findings regarding bed homogeneity are calculated using the Lacey method [1] for quantitative analysis and visual observations have been read out for qualitative assessment. Particles inhomogeneity is at its minimum when more ploughs mated to the screw were used.