| Entered for the 21st century, our country's agricultural production sets a higher request to the agricultural mechanization. Following the massive agricultural products primarily to transform gradually by quantity into by the quality, and also day by day renewing to the agricultural mechanization requests, the variety and quantity of the agricultural mechanization promotes in a large scale, and the agricultural mechanization also gradually transforms by the pure quantity increase into the quality and the technical level enhancement.Our country is a large agricultural nation. The agriculture is the foundation of the national economy, and the mechanization of agriculture equipment degree and the mechanized level height is the main symbol of the agriculture modernization. The agricultural mechanization is the important tool of the agricultural production, is one of the important attributes of developing the agricultural productive forces, and is the carrier of realizing the agricultural science and farming techniques. There is an extremely vital significance to the social stability and the economical development by maintaining the agriculture stabled. Therefore, if the agriculture wants to realize the modernization, it should first realize the comprehensive mechanization of the agricultural production.The fertilizer apparatus is an important part on the seeder and the fertilizer applicator, its operating performance affects directly the seeder and the fertilizer applicator work quality in, relates the fertilizer's distributing precision in the line and in the depth, relates the rate of seedlings emergence of sowing seeds, and relates the balance, stable and the grain yield of the complete machine.At present, outer-fluted fertilizer apparatus is the most designed and researched in the domestic and foreign. The traditional method of fertilizer apparatus designing mainly depends upon designer's experience or the testing method, and is unable to satisfy the modern agriculture the need. Therefore, in order to enhance the fertilizer apparatus the working efficiency and the design level better, this article uses the discrete element method (DEM) to study the work process of fertilizer apparatus. Using the analysis software based on the DEM of our topic-based group research and development to carry on the digitized design and the research to the fertilizer apparatus, thus a new kind of digitization method to fertilizer apparatus was established.This article taks the core of seeder—a kind of outer-fluted fertilizer apparatus and fertilizer granular as the object of study, and established a DEM analyze the model of fertilizer granular. On the base of carring on the test to main physical mechanics characteristic of fertilizer granular, using the analysis software based on the DEM of our topic-based group independent research and development, we carry on the simulation analysis to the work process of outer-fluted fertilizer apparatus.According to the require of the DEM to analyze and calculation, in this paper some properties of physical mechanics characteristic of two kinds of fertilizer granular (ShanDong-4 andDaQing-3) are measured or tested. and the analysis results of the fertilizer granular normal stiffness test show:①Both the loading speed with 6N/s to 15N/s and the size of fertilizer granular have little effect on the stiffness coefficient;②When the deformation rate is between 4mm/s and15mm/s, the stiffness coefficient have little effect;③The dimension and figure of fertilizer granular have lots infection on the stiffness coefficient, Under the same condition the stiffness, For example the stiffness of DaQing-3 with 12% (w.b.)and the loading speed with 10N/s, it is 36N/m~80 N/m while the stiffness of DaQing-3 is 47N/m~83 N/m. The stiffness with the diameter of 4mm of the fertilizer granular is bigger than that with the diameter of 3mm of the fertilizer granular;④The stiffness is decreasing with the increasing containing water or moisture;⑤Fertilizer granular differ in breed ,the stiffness coefficient have carry weight effect.The experiments results of friction coefficient illuminate:①with the increased sheet speed , the friction coefficient is immovable,the bound of change of the loading speed is fluctuated ,it is little dependence on the contacting;②Two kinds of fertilizer granular and the surface material contacting with the increasing containing water or moisture of the friction coefficient is increased become relaxly.③Under the same condition the stiffness, the friction coefficient between the Two kinds of fertilizer granular and cast iron is bigger than plastic and glass; For example the friction coefficient of DaQing-3 with normal loading 1.0N, the sheet speed of 8000mm/min, the friction coefficient of fertilizer granular (w.b.) with the cast iron surface is 0. 38, the plastic surface is 0.26 and the glass surface is 0.12.④when the same condition, the kinds of breed has an apparent effect on it, The friction coefficient of ShanDong-4 is bigger than that of DaQing-3;Make an experiment on fertilizer granular impact with the cast iron, the glass ,the plastic and the fertilizer granular; The collision coefficient of restitution are measured or tested and the result of stiffness coefficient shows: Under the same condition, the collision coefficient of restitution the kinds of fertilizer granular the glass is biggest amongst the plastic, the cast iron and the fertilizer granular, For example The collision coefficient of restitution of ShanDong-4 impact with the cast iron is 0.208~0.298, the plastic is 0.467~0.645andthe fertilizer granular is 0.207~0.383. It shows that the collision coefficient of restitution have something to do with material, In addition The collision coefficient of restitution of fertilizer granular is lower with the increment of humidity;According to the measurement or test results of two kinds of fertilizer granular, we carry on the simulation analysis to the work process of outer-fluted fertilizer apparatus by the 2-dimension DEM soft with design and evaluation developed by our team. we carry out an experiment in alter the rotate speed of the outer-fluted wheel and the radium of outer-fluted wheel, The results of simulation explain:①With the increase of the rotate speed of the outer-fluted wheel, a large amount of fertilization becomes big.②The radium of outer-fluted wheel shows a good many impact on fertilization power, With the increased the radium of outer-fluted wheel ,it power is augmented. For in the main,The rotate speed of the outer-fluted wheel and the radium of outer-fluted wheel gives cause for fertilization power increasely. It offer gist that a parameter design of the analysis software based on the DEM, It is a new method to digital design working parts of the fertilizer apparatus and analyze the capability. It becomes the foundation of simulation analysis of the DEM for mechanical part with complex construction and motion mode. |
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