变量施肥系统的设计与研究

发布时间：2018-05-25 20:57

本文选题：双变量施肥 + 肥料物理力学特性　；参考：《石河子大学》2017年硕士论文

【摘要】：农田施肥中存在化肥投放量大、肥料过量偏施、化肥利用率偏低、投入产出比较低等问题,并由此引起了农产品质量下降、地下水污染、水体富营养化。为了减少肥料的投放量,实现肥料的合理施用,设计出一种双变量施肥机,在离散元软件中进行了颗粒肥料的仿真排肥试验,并设计试制双变量施肥试验装置,在试验装置上进行排肥试验,主要研究内容如下:(1)针对颗粒肥料的物理力学特性进行了试验测定,主要对磷酸二铵的三维尺寸、颗粒的真实密度和堆积密度等物理特性以及其动静摩擦系数、休止角、碰撞恢复系数、刚度系数和剪切模量等力学特性进行了测定。然后对测定结果进行讨论分析,为下一步变量施肥机的设计及离散元法分析时确定合适的参数提供依据。(2)根据田间施肥量需求和机具作业速度,确定变量施肥系统的整体方案,包括施肥机排肥机构、施肥机整体结构和控制系统的确定;设计出双变量施肥机,主要包括双变量外槽轮排肥器、螺旋式外槽轮、转速开度调节机构、柔性开沟覆土装置和不等容积的肥箱等关键机构的设计以及双变量施肥机液压系统设计与附件选择。(3)在离散元软件进行肥料颗粒和排肥器的建模,进行直槽式槽轮与螺旋式槽轮排肥器仿真排肥试验,对两种外槽轮排肥器进行了排肥稳定性分析;利用离散元软件进行多种转速开度组合下的仿真排肥试验;搭建双变量试验装置,进行排肥试验,将试验结果同离散元软件上进行的仿真排肥试验结果进行对比,得出仿真试验与排肥装置上进行的排肥试验的排肥量随转速开度改变的变化趋势一致,证明了采用离散元素法分析外槽轮式排肥器的有效性和可行性。(4)分析排肥轴转速与排肥量之间的关系,排肥轴开度与排肥量之间的关系以及排肥轴转速、开度两个变量耦合时,两变量与排肥量之间的关系,并对各种影响因素进行了排肥器的排肥稳定性和均匀性分析。
[Abstract]:There are some problems in fertilizer application, such as large amount of fertilizer, excessive application of fertilizer, low utilization rate of fertilizer, low input-output and so on, which leads to the decline of agricultural product quality, groundwater pollution and eutrophication of water body. In order to reduce the amount of fertilizer and realize the rational application of fertilizer, a kind of two-variable fertilizer machine was designed, and the simulated fertilizer discharge test of granular fertilizer was carried out in discrete element software, and the experiment device of two-variable fertilizer was designed. The main contents of this experiment are as follows: (1) the physical and mechanical properties of granular fertilizer were tested, and the three-dimensional size of diammonium phosphate was measured. The physical properties, such as real density and packing density of particles, as well as the dynamic and static friction coefficient, angle of repose, collision recovery coefficient, stiffness coefficient and shear modulus were measured. Then the test results are discussed and analyzed, which provides the basis for the design of the next variable rate fertilization machine and the determination of the appropriate parameters when the discrete element method is used to determine the appropriate parameters.) according to the field fertilization requirements and the speed of the machine and tools, the overall scheme of the variable rate fertilization system is determined. It includes fertilizer discharging mechanism, the whole structure and control system of fertilization machine, and the design of double variable fertilizer application machine, which mainly includes double variable external slot wheel fertiliser, spiral external groove wheel, speed opening adjusting mechanism, and so on. The design of key mechanisms, such as flexible trench covering device and unequal volume fertilizer box, as well as the design of hydraulic system of two-variable fertilization machine and the selection of accessories, are modeled in discrete element software, such as fertilizer particle and fertiliser. In this paper, the emulation experiment of fertiliser with straight slot wheel and spiral groove wheel is carried out, and the stability of the two kinds of external slot wheel is analyzed, and the simulation experiment is carried out by using discrete element software under the combination of various rotational speed opening degree. A bivariate experiment device was set up to carry out the fertilizer discharge test. The results of the experiment were compared with the results of the simulation experiment conducted on the discrete element software. It is concluded that the variation trend of the amount of fertilizer discharged with the speed opening degree is consistent with that of the emulation test and the fertilizer discharge experiment carried out on the fertiliser device. It is proved that the discrete element method is effective and feasible to analyze the efficiency and feasibility of the external grooved wheel type fertiliser.) the relationship between the rotation speed of the discharge shaft and the amount of fertilizer discharge, the relationship between the opening degree of the discharge axis and the discharge amount, and the coupling of the rotation speed and the opening degree of the discharge shaft are analyzed. The relationship between the two variables and the amount of fertilizer excretion was studied. The stability and uniformity of the effluents of various factors were analyzed.
【学位授予单位】：石河子大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S224.2

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