基于散粒体动力学的水田侧深施肥装置的分析方法和试验

发布时间：2018-03-07 05:33

本文选题：散粒体　切入点：离散元法　出处：《东北农业大学》2015年硕士论文　论文类型：学位论文

【摘要】：水田化肥深施技术可以有效提高水稻产量,减少肥料损失和环境的污染。水田深施肥过程中容易出现肥料架空、板结,造成排肥堵塞,影响施肥质量。掌握肥料在施肥装置中的流动规律可以有助于设计合理、高效的水田深施肥装置。肥料颗粒是农业散粒体物料,离散元法是研究散粒体受力、运动等方面的一种重要方法,本文采用离散元法对肥料在水田深施肥装置中运动过程进行研究。根据离散元法计算要求,以大颗粒尿素肥料为研究对象,测试分析了肥料的物理力学特性参数,得到肥料颗粒的离散元模型;建立了水田深施肥装置离散元边界模型,并确定边界接触类型。仿真肥料颗粒在水田深施肥装置的不同工作状态下的运动过程。借助高速摄像拍摄肥料在深施肥装置的运动形态,将试验结果与仿真结果进行对比分析。主要研究工作如下:(1)通过物理力学特性测试试验测量了肥料颗粒的三轴尺寸、等效直径、球形率、密度等基本物理参数;得到了肥料颗粒的弹性模量、静摩擦系数、滚动摩擦系数、碰撞恢复系数并分析了各自主要影响因素的关系,为颗粒仿真分析提供了参数依据。(2)采用仿真与试验结合的参数标定法,通过分析球形颗粒和手动填充的不规则球形颗粒的休止角及不同参数的影响关系,验证了单个肥料颗粒参数测量对群体颗粒运动仿真建模的有效性。综合仿真效率,得到了肥料颗粒离散元模型。(3)以安装有螺旋钢丝为扰动部件的水田深施肥装置为研究对象,为仿真试验设计了简化的肥箱结构,确定了肥箱的运动参数和材料属性,建立了水田深施肥装置的离散元分析实体边界模型。选择颗粒之间、颗粒与深施肥装置模型之间的接触计算方法。(4)仿真分析了肥料在有无转动螺旋钢丝情况下的落肥过程以及螺旋钢丝的结构参数对肥箱排肥的影响仿真、肥箱开口直径对肥箱工作状态的影响仿真。观察肥料颗粒在不同工作条件下的流动形态,分析了不同装置结构对颗粒流动的影响。(5)采用高速摄像技术对肥料颗粒运动过程进行判别分析。将试验分析结果与仿真结果进行对比,初步证明了肥料颗粒计算参数选取的合理性和采用离散元法分析肥料颗粒与施肥装置机械部件接触作用的可行性,为肥料颗粒建模、水田深施肥装置的设计建立了一种新方法。
[Abstract]:Deep application of fertilizer in paddy fields can effectively increase rice yield, reduce fertilizer loss and environmental pollution. Mastering the flow rule of fertilizer in fertilizer plant can be helpful to design rational and efficient deep fertilizing device in paddy field. Fertilizer particle is agricultural granular material, discrete element method is to study the force of loose grain. In this paper, a discrete element method is used to study the movement process of fertilizer in a paddy field deep fertilizing plant. According to the requirements of discrete element method, a large granular urea fertilizer is used as an object of study. The parameters of physical and mechanical properties of fertilizer were measured and analyzed, and the discrete element model of fertilizer particle was obtained, and the discrete element boundary model of paddy field deep fertilization device was established. The boundary contact type was determined, and the movement process of fertilizer particles in different working states of paddy field deep fertilization device was simulated. The motion pattern of fertilizer in deep fertilization device was photographed by high speed camera. The main research work is as follows: 1) the basic physical parameters such as triaxial size, equivalent diameter, spherical rate, density and so on are measured by physical and mechanical properties test. The elastic modulus, static friction coefficient, rolling friction coefficient and impact recovery coefficient of fertilizer particles were obtained. The parameter calibration method combined with simulation and experiment is used to analyze the angle of repose of spherical particles and the influence of different parameters on the angle of repose of spherical particles and the irregular spherical particles filled by hand. The effectiveness of single fertilizer particle parameter measurement on simulation modeling of mass particle motion was verified. The discrete element model of fertilizer particle was obtained by synthesizing the simulation efficiency. The paddy field deep fertilizing device with spiral steel wire as disturbance component was used as the research object. The simplified fertilizer box structure was designed for the simulation test, the motion parameters and material properties of the fertilizer box were determined, and the discrete element analysis entity boundary model of the paddy field deep fertilization device was established. The contact calculation method between particle and deep fertilization device. (4) Simulation analysis of fertilizer falling process under the condition of rotating spiral steel wire and the influence of structural parameters of spiral steel wire on fertiliser discharge. Simulation of the influence of the opening diameter of the fertiliser box on the working state of the fertiliser box. The effect of different device structures on particle flow is analyzed. (5) High-speed camera technology is used to discriminate and analyze the motion process of fertilizer particles. The experimental results are compared with the simulation results. The rationality of calculating parameters of fertilizer particles and the feasibility of using discrete element method to analyze the contact between fertilizer particles and mechanical parts of fertilizer plant were preliminarily proved. A new method was established for modeling fertilizer particles and designing a deep fertilizing device in paddy fields.
【学位授予单位】：东北农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S224.2

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