{"id":{"repo_id":"iastate","oai_identifier":"oai:dr.lib.iastate.edu:20.500.12876/106807"},"canonical_url":"https://search.dev.ndltd.org/etd/iastate/oai:dr.lib.iastate.edu:20.500.12876/106807","repository":{"repo_id":"iastate","name":"Iowa State University","base_url":"https://dr.lib.iastate.edu/server/oai/request"},"display":{"title":"Simulation of urea particle flow using DEM for dry fertilizer spreading optimization","abstract":"Uniformity of dry fertilizer spread pattern relies on the accurate representation of bulk material behavior during handling, discharge, and impact. This study aims to develop a discrete element method (DEM) model for urea and assessed it through a calibration and multi-method validation framework pertinent to fertilizer spreader applications. Urea was first characterized experimentally for particle size and density, and the DEM particles were represented as single spheres with a mean diameter of 3.2 mm. A full-factorial design of experiment was then used to calibrate the model using two bulk responses: angle of repose and loose-fill bulk density. The calibrated parameter set consisted of a particle-particle static friction coefficient of 0.27 and a rolling friction coefficient of 0.11. With this set, the DEM model predicted angle of repose and bulk density with percent relative errors of 10.02% and 7.50%, respectively. The calibrated model was then validated using two independent experiments: hopper discharge through a 100 mm square orifice and bulk particle impact on a 25° inclined plate. For hopper discharge, the model predicted a steady-state mass flow rate of 4.40 kg s⁻¹ compared with the experimental value of 4.83 kg s⁻¹, giving a percent relative error of 8.85%. For the impact-plate test, the DEM model predicted an accumulated mass of 2.50 kg·s compared with an experimental mean of 2.26 kg·s, with a percent relative error of 10.56%. The projected particle–plate contact area showed the closest agreement, with a DEM prediction of 102,039 mm² compared with an experimental mean of 103,520 mm², corresponding to a percent relative error of −1.43%. Overall, the results show that calibration based on angle of repose and bulk density can produce a DEM model that predicts gravity-driven discharge and post-impact spreading behavior with reasonable accuracy. At the same time, the larger error in accumulated mass suggests that impact-related retention and collision behavior may require additional calibration parameters in future work.","abstract_html":"Uniformity of dry fertilizer spread pattern relies on the accurate representation of bulk material behavior during handling, discharge, and impact. This study aims to develop a discrete element method (DEM) model for urea and assessed it through a calibration and multi-method validation framework pertinent to fertilizer spreader applications. Urea was first characterized experimentally for particle size and density, and the DEM particles were represented as single spheres with a mean diameter of 3.2 mm. A full-factorial design of experiment was then used to calibrate the model using two bulk responses: angle of repose and loose-fill bulk density. The calibrated parameter set consisted of a particle-particle static friction coefficient of 0.27 and a rolling friction coefficient of 0.11. With this set, the DEM model predicted angle of repose and bulk density with percent relative errors of 10.02% and 7.50%, respectively. The calibrated model was then validated using two independent experiments: hopper discharge through a 100 mm square orifice and bulk particle impact on a 25° inclined plate. For hopper discharge, the model predicted a steady-state mass flow rate of 4.40 kg s⁻¹ compared with the experimental value of 4.83 kg s⁻¹, giving a percent relative error of 8.85%. For the impact-plate test, the DEM model predicted an accumulated mass of 2.50 kg·s compared with an experimental mean of 2.26 kg·s, with a percent relative error of 10.56%. The projected particle–plate contact area showed the closest agreement, with a DEM prediction of 102,039 mm² compared with an experimental mean of 103,520 mm², corresponding to a percent relative error of −1.43%. Overall, the results show that calibration based on angle of repose and bulk density can produce a DEM model that predicts gravity-driven discharge and post-impact spreading behavior with reasonable accuracy. At the same time, the larger error in accumulated mass suggests that impact-related retention and collision behavior may require additional calibration parameters in future work.","abstract_has_math":false,"creators":["Kosaraju , Satya , Venkatesh"],"institution":"Iowa State University - Thesis & Dissertation","degree_name":"Master of Science","degree_level":"thesis","degree_discipline":"Agricultural engineering","degree_department":null,"school":null,"contributors":[],"advisors":["Tekeste, Mehari, Z"],"committee_chairs":[],"committee_members":[],"year":2026,"date_issued":"2026-05","date_published":"2026-05","updated_at":"2026-07-24T02:37:16Z","subjects":["Agricultural and biosystems engineering"],"languages":["en_US"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://dr.lib.iastate.edu/handle/20.500.12876/106807","outbound_label":"Repository record","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Tekeste, Mehari, Z"]},{"key":"dc:creator","label":"Author","values":["Kosaraju , Satya , Venkatesh"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2026-06-10T19:09:41Z"]},{"key":"dc:date.issued","label":"Date","values":["2026-05"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Agricultural engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Iowa State University - Thesis & Dissertation"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Agricultural and biosystems engineering"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en_US"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://dr.lib.iastate.edu/handle/20.500.12876/106807"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["May2026"]},{"key":"dc:description.abstract","label":"Abstract","values":["Uniformity of dry fertilizer spread pattern relies on the accurate representation of bulk material behavior during handling, discharge, and impact. This study aims to develop a discrete element method (DEM) model for urea and assessed it through a calibration and multi-method validation framework pertinent to fertilizer spreader applications. Urea was first characterized experimentally for particle size and density, and the DEM particles were represented as single spheres with a mean diameter of 3.2 mm. A full-factorial design of experiment was then used to calibrate the model using two bulk responses: angle of repose and loose-fill bulk density. The calibrated parameter set consisted of a particle-particle static friction coefficient of 0.27 and a rolling friction coefficient of 0.11. With this set, the DEM model predicted angle of repose and bulk density with percent relative errors of 10.02% and 7.50%, respectively. The calibrated model was then validated using two independent experiments: hopper discharge through a 100 mm square orifice and bulk particle impact on a 25° inclined plate. For hopper discharge, the model predicted a steady-state mass flow rate of 4.40 kg s⁻¹ compared with the experimental value of 4.83 kg s⁻¹, giving a percent relative error of 8.85%. For the impact-plate test, the DEM model predicted an accumulated mass of 2.50 kg·s compared with an experimental mean of 2.26 kg·s, with a percent relative error of 10.56%. The projected particle–plate contact area showed the closest agreement, with a DEM prediction of 102,039 mm² compared with an experimental mean of 103,520 mm², corresponding to a percent relative error of −1.43%. Overall, the results show that calibration based on angle of repose and bulk density can produce a DEM model that predicts gravity-driven discharge and post-impact spreading behavior with reasonable accuracy. At the same time, the larger error in accumulated mass suggests that impact-related retention and collision behavior may require additional calibration parameters in future work."]},{"key":"dc:format.mimetype","label":"Dc Format Mimetype","values":["PDF"]},{"key":"dc:title","label":"Title","values":["Simulation of urea particle flow using DEM for dry fertilizer spreading optimization"]}]}],"canonical_facts":{"dc:contributor.advisor":["Tekeste, Mehari, Z"],"dc:creator":["Kosaraju , Satya , Venkatesh"],"dc:date.accessioned":["2026-06-10T19:09:41Z"],"dc:date.issued":["2026-05"],"dc:description":["May2026"],"dc:description.abstract":["Uniformity of dry fertilizer spread pattern relies on the accurate representation of bulk material behavior during handling, discharge, and impact. This study aims to develop a discrete element method (DEM) model for urea and assessed it through a calibration and multi-method validation framework pertinent to fertilizer spreader applications. Urea was first characterized experimentally for particle size and density, and the DEM particles were represented as single spheres with a mean diameter of 3.2 mm. A full-factorial design of experiment was then used to calibrate the model using two bulk responses: angle of repose and loose-fill bulk density. The calibrated parameter set consisted of a particle-particle static friction coefficient of 0.27 and a rolling friction coefficient of 0.11. With this set, the DEM model predicted angle of repose and bulk density with percent relative errors of 10.02% and 7.50%, respectively. The calibrated model was then validated using two independent experiments: hopper discharge through a 100 mm square orifice and bulk particle impact on a 25° inclined plate. For hopper discharge, the model predicted a steady-state mass flow rate of 4.40 kg s⁻¹ compared with the experimental value of 4.83 kg s⁻¹, giving a percent relative error of 8.85%. For the impact-plate test, the DEM model predicted an accumulated mass of 2.50 kg·s compared with an experimental mean of 2.26 kg·s, with a percent relative error of 10.56%. The projected particle–plate contact area showed the closest agreement, with a DEM prediction of 102,039 mm² compared with an experimental mean of 103,520 mm², corresponding to a percent relative error of −1.43%. Overall, the results show that calibration based on angle of repose and bulk density can produce a DEM model that predicts gravity-driven discharge and post-impact spreading behavior with reasonable accuracy. At the same time, the larger error in accumulated mass suggests that impact-related retention and collision behavior may require additional calibration parameters in future work."],"dc:format.mimetype":["PDF"],"dc:identifier.uri":["https://dr.lib.iastate.edu/handle/20.500.12876/106807"],"dc:language.iso":["en_US"],"dc:subject":["Agricultural and biosystems engineering"],"dc:title":["Simulation of urea particle flow using DEM for dry fertilizer spreading optimization"],"dc:type":["Thesis"],"thesis:degree_discipline":["Agricultural engineering"],"thesis:degree_level":["thesis"],"thesis:degree_name":["Master of Science"],"thesis:institution_name":["Iowa State University - Thesis & Dissertation"]},"updated_at":"2026-07-24T02:37:16Z"}