| By adopting two types of outer groove-wheel fertilizer apparatuses with differentstructures and four kinds of composite particle fertilizer as the research objects, thedissertation has developed a new approach for groove-wheel fertilizer apparatus analysis andoptimization design. Firstly, according to the three-dimensional CAD model of fertilizerapparatus, its three-dimensional discrete element method (DEM) analysis model is built.Using spherical particles, four ball ellipsoid particles and the method of three-dimensionalentity scan combining with balls, the fertilizer particle analysis model is established. Then,by using linear viscoelastic model, the contact forces between particle and particle or particleand fertilizer apparatus are calculated. Using self-designed three-dimensional AgriDEMsoftware, the working process and performance of fertilizer apparatus is analyzed. Further,by changing the CAD model of the device, fertilizer apparatus with different structures andsizes are analyzed. Meanwhile, the DEM results are compared with EDEM simulation andplatform test results. The results preliminarily proved the validity and effectiveness of DEManalysis. The specific work is as follows:1) According to the simulation requirement of fertilizer apparatus operation using DEM,the dissertation has chosen four different fertilizer particles (①Beijing,②Daqing,③Shandong,④Jilin) as the research objects. By experiments, the physical andmechanical characteristics of the fertilizer granules have been determined, and the influencefactors on the mechanical properties have been studied emphasisly, which include moisturecontent, fertilizer particle density, three axis sizes, stiffness coefficient, dynamic/staticfriction coefficients, crash recovery coefficient, and modulus of elasticity, etc. Then, themeasure results were discussed and analyzed to provide a basis for the appropriateparameters of DEM analysis in the next step.2) The working process of fertilizer apparatus based on DEM are studied emphasisly. Byadopting two types of outer groove-wheel fertilizer apparatuses with different structures andfour kinds of composite particle fertilizer as the research objects, using3D scanner to scanthe fertilizer particle profile data, four kinds of fertilizer manual filling particles model basedon3D scanning data were set up, meanwhile, the automatic filling particles model offertilizer particles were founded by the research group developed TDEM software. Adoptingthe modeling method of CAD and according to the Pro/ENGINEER solid model of thefertilizer apparatus, the three-dimensional DEM model was established. Take the sphericalparticles combination method, the DEM calculation method for irregular fertilizer particles have been initially established.3) By adopting two different self-designed outer groove-wheel fertilizer apparatus usingorganic glass, choosing four kinds of fertilizers (①Beijing,②Daqing,③Shandong,④Jilin)and using a PSJ seed meter performance test rig as the test equipment, the bench test foractual working process of the fertilizer apparatus is conducted. In the test, four differentfertilizer shaft speeds(31.24r/min,40.87r/min,50.63r/min), three outer groove-wheelworking lengths (20mm,40mm,60mm), three fertilizing tongue angles (15°,30°,45°) arechoose as the experimental conditions. The influence of fertilizer process on fertilizerconsumption quantity is analyzed. By the aid high-speed CCD camera, the real-time motorprocesses of the fertilizers are recorded. Then, through the BLASTER’s MAS, the movementrule of the fertilizer particles in fertilizer apparatus is examined further. The results provide adata reference for the following DEM analysis.4) Using DEM to simulate and analyze the working process of outer groove-wheelfertilizer apparatus. Two types of outer groove-wheel fertilizer apparatuses with differentstructures and four kinds of composite particle fertilizer (①Beijing,②Daqing,③Shandong,④Jilin) are chosen as the research objects. According to the three-dimensional CAD modelof fertilizer apparatus, the three-dimensional DEM analysis model is established. Usingspherical particles and ellipsoid particles, the analysis model of fertilizer particles isestablished. By using linear viscoelastic model, the contact forces between particle andparticle or particle and fertilizer apparatus are calculated. Using self-designedthree-dimensional AgriDEM software, the working process and performance of fertilizerapparatus is analyzed. Further, by changing the CAD model of the device, fertilizerapparatus with different structures and sizes are analyzed. Meanwhile, by the contrastiveanalysis of DEM results and experimental results in chapter4, it is found that they aresimilar and have the same variation trend, which preliminarily prove the feasibility andeffectiveness of DEM analysis applying to the fertilizer apparatus. Thus, the dissertation hasproposed a new approach for the study and optimization design of outer groove-wheelfertilizer apparatus. |
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