| Rubber trees has become an important crop in tropical and subtropical areas because of rubber’s good physical properties and chemical stability.Fertilization has an important effect on the growth of rubber trees.Restricted by the humid climate conditions in South China,the effect of rubber tree fertilization machinery is poor,there is a waste of fertilizer and it is difficult to clean up the facilities after fertilization,so the optimization and improvement of rubber fertilization machinery is imminent.The difficulty of rubber fertilization is the quantitative disposal of fertilizer and solving the problem of fertilizer adhesion.Through field investigation of rubber tree planting site,the type and characteristics of fertilizer required by rubber tree and the working situation of fertilizer discharging device of fertilization machinery were understood.Based on the principle of discrete element,a scraper type fertilizer discharging device was designed and optimized with the assistance of relevant software.The main research contents and results are as follows:(1)Based on the research of domestic and foreign literature,combined with the field investigation at the rubber planting base of the Agricultural Machinery Institute of the Chinese Academy of Tropical Agricultural Sciences in Zhanjiang,Guangdong Province,the planting agronomic requirements,growing environment and fertilizer application of rubber tree were got.The rubber granule fertilizerwas select as the fertilizer research object in the fertilizer application experiment,the method of scraper fertilizer discharge was used to simulate the fertilizer discharge device and to optimize its parameters.(2)Referring to the material related to the physical and chemical characteristics of rubber granule fertilizer,and take the related physical and chemical parameters measurement test,physical and chemical parameters of rubber granule fertilizer were determined,namely static friction coefficient is 0.4,dynamic friction factor is 0.3,recovery coefficient is 0.3,density is 1.68kg/m-3,elastic modulus is 8.51×10~7,and poisson’s ratio is 0.25.(3)Referring to the structure design and working principle of other rubber tree fertilizer applicators,combining with the interaction between fertilizer ejector and fertilizer,a kind of scraper fertilizer applicator was designed.According to the agronomic requirements of rubber tree fertilization,the amount of fertilizer application was determined,and the related structure parameters of fertilizer discharge device were determined.(4)Through Solidworks2018,the 3D modeling and the whole assembling of the scraper fertilizer discharge device were made,and the whole design of the fertilizer discharge device was visualized.(5)The process of fertilizer discharge was simulated by Edem2018 software,and the main factors affecting the fertilizer discharge were determined as follows:scraper opening,disc rotation speed and scraper angle.The orthogonal experiment was designed by Design Expert software,and the simulation experiment was carried out by using EDEM2018software,and the data of fertilizer discharge was obtained,the influence degree of the factors is determined as follows:the scraper opening>the rotating speed of the disc>the angle of the scraper.Optimum parameter combination were obtained,that is:the scraper opening is 25.4 cm,the angle of the scraper is 54.1°,and the rotating speed of the disc is5.4 r/min.Through the field experiment at the Institute of Agricultural Machinery,Zhanjiang Academy of Tropical Agricultural Sciences,Guangdong Province,the combination of these parameters could be proved to achieve the best effect of fertilizer discharge. |
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