玉米秸秆捡拾粉碎沟埋还田机研究

发布时间：2018-01-06 12:19

本文关键词：玉米秸秆捡拾粉碎沟埋还田机研究　出处：《中国农业大学》2017年博士论文　论文类型：学位论文

【摘要】：农作物秸秆是农业生产系统中的重要副产品,既是一项重要的生物资源,也是耕地的营养源,采用秸秆还田有利于提升耕地质量,实现可持续农业发展。针对我国玉米种植区地表秸秆量大、影响后期耕播作业的问题,以降低表层秸秆含量、改善全耕层土壤有机质状况出发,设计了一种秸秆捡拾粉碎沟埋还田机。主要研究成果包括:(1)针对提出的秸秆捡拾粉碎沟埋还田技术方案,通过文献分析与虚拟装配设计,提出了弹齿上抛秸秆、动定刀支撑粉碎秸秆、挡草板调控秸秆掩埋比例、抛送板抛送秸秆以及顺序开沟、落草、覆土掩埋等关键匹配设计方案。(2)依据捡拾玉米长秸秆或整株玉米秸秆的技术要求,分析确定了捡拾弹齿在每个阶段的摆动姿态与运动规律,在此基础上建立了导向滑道模型,并确定了弹齿上抛秸秆的条件。通过仿真分析优化,确定了捡拾装置的结构参数和工作参数。(3)论文完成了动定刀支撑切割粉碎装置的参数设计,并在流体力学分析软件Fluent中建立了粉碎腔内气流流场分析模型,获得了气流流场的基本特征。通过气流测试试验验证了利用Fluent软件对粉碎腔气流流场进行模拟分析的方法是正确可信的。研究发现,粉碎腔入口处与出口处均出现了涡流现象,且其涡流强度随转速的增加而增强,这将对秸秆的进入与抛出产生影响。采用折线形壳体能够使靠近壁面的气流速度和压力剧烈变化,从而改变粉碎过程中秸秆的运动状态,能在一定程度上延长秸秆在腔内停留的时间,从而提高秸秆的粉碎程度。(4)运用离散元素法分析了碎秸秆物料在送埋装置内的运动规律,通过改变抛送板叶片倾角、旋转轴转速和喂入量,利用EDEM软件进行模拟分析,得出抛送板叶片角度为0°、旋转速度为180r/min时,抛送板的整体抛送性能较好,送埋装置能够在喂入量为设计值(1.1kg/s)1.5倍范围内变化条件下正常工作。(5)田间试验表明在不同秸秆掩埋比例条件下整机工作性能稳定,秸秆粉碎长度合格率为92.6%,开沟深度稳定性为95%,秸秆入沟率与设定掩埋比例间的偏差在10%范围内,覆土层平均厚度为94.9mm,各项技术指标基本满足技术要求,达到预期设计目标。
[Abstract]:Crop straw is an important by-product of agricultural production system, is an important source of nutrition and biological resources, the cultivated land, the use of straw is conducive to enhancing the quality of cultivated land and realize the sustainable development of agriculture. In view of our country corn planting area surface large amount of straw, the late sowing effect of the operation, in order to reduce the surface content of straw to improve the status of soil organic matter, total soil, design a straw crushing returning machine pick up buried. The main results are as follows: (1) put forward the straw crushing returning pick up buried technology solutions, through literature analysis and virtual assembly design, the elastic tooth throwing straw, moving knife support crushed straw. Grass in regulation of straw buried proportion, throwing in throwing straws and order ditching, were gone, soil buried and other key matching design. (2) on the basis of picking up the corn straw or whole maize straw The technical requirements, analysis of the oscillating attitude and movement of spring tooth picking at each stage, set up on the basis of the guide slide model and elastic tooth throwing straw conditions were determined. Through simulation analysis and optimization, structure parameters and working parameters of the pick-up device was determined. (3) this paper has completed the design of dynamic parameter cutting knife support crushing device, and the fluid mechanics analysis software Fluent analysis model is established for cavity flow crushing, obtained the basic characters of the airflow field. Through the air test method was applied to simulate the crushing cavity flow field using Fluent software is correct and reliable. The study found that the crushing cavity and the entrance the exit appeared vortex phenomenon and its vortex intensity with the speed increase, which will affect the entry and straw thrown. Using the line shaped shell is capable to rely on Dramatic changes in the near wall flow velocity and pressure, thus changing the motion state of the crushing process of straw, to a certain extent, prolong the residence time of straw in the cavity, so as to improve the degree of grinding of straw. (4) using the discrete element method analysis of broken straw material in the movement with the device, by changing the cast send plate blade angle, rotation speed and feed rate, were simulated and analyzed using EDEM software, the throwing plate blade angle is 0 degrees, the rotating speed is 180r/min, the whole cast plate feeding throwing good performance to send, send for the design in the embedded device can feed (1.1kg/s) working condition within the range of 1.5 times. (5) the field test show that the stability of the whole machine performance in different proportion of straw buried under the condition of straw crushing pass rate of length 92.6%, planting depth stability was 95%, the straw into the ditch rate and set the proportion of the buried In the range of 10%, the average thickness of the overburden is 94.9mm. The technical specifications meet the technical requirements and achieve the desired design goals.

【学位授予单位】：中国农业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：S224.29

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