秸秆-土壤-旋耕刀系统中秸秆位移仿真分析  

Simulation Analysis of Straw Movement in Straw-Soil-Rotary Blade System

作　　者：方会敏[1] 姬长英[1] Ahmed Ali Tagar 张庆怡[1] 郭俊[1] 

机构地区：[1]南京农业大学工学院,南京210031 [2]信德农业大学农业工程学院,坦杜阿拉亚70060

出　　处：《农业机械学报》2016年第1期60-67,共8页Transactions of the Chinese Society for Agricultural Machinery

基　　金：国家自然科学基金项目(51275250);江苏省2013年度普通高校研究生科研创新计划项目(CXZZ13_0282)

摘　　要：秸秆-土壤-旋耕刀之间的相互作用机理对于分析耕作过程有着重要作用。为研究秸秆-土壤-旋耕刀的宏观及微观相互作用,对系统中的秸秆位移进行了仿真分析。首先建立了秸秆-土壤-旋耕刀相互作用的三维离散元模型;其次,对仿真结果与室内土槽实验结果进行对比分析,在土槽实验中采用示踪器方法测量秸秆位移;仿真中导出每个时刻的秸秆位置用来描述秸秆仿真位移;最后,利用仿真数据对秸秆位移进行三维分析。实验和仿真都在恒定前进速度0.222 m/s和耕深100 mm及4种转速(77、100、123、146 r/min)下进行。实验与仿真结果皆显示秸秆位移随着转速增加呈现增加的趋势;秸秆的水平运动位移总是大于同转速下的侧向位移;高转速下的实验与仿真位移误差约为40%,低转速下为70%。利用拟合的误差方程和仿真值可以估算秸秆的水平和侧向位移值,估算值与实验值误差为8.7%和9.3%。通过追踪不同位置的秸秆颗粒发现:初始位置不同的秸秆颗粒具有不同的运动:位于正切刃内侧的秸秆在刀刃切开土壤时,沿正切刃边缘滑出;而位于侧切刃下方的秸秆在开始时被侧切刃挤压随刀刃一起运动,而后随土壤一起被抛起;远离旋耕刀工作范围的秸秆,则因受土壤扰动影响而仅有微小的位移。紧靠侧切刃及过渡刃周围的秸秆颗粒在考察时间段内被直接旋耕入土。可以利用秸秆的垂直方向受力情况,优化旋耕刀刃口曲线提高秸秆在旋耕过程中直接入土的比例;还可以整合秸秆水平和侧向位移及分布,寻找最优工作参数使秸秆在3个方向都能均匀分散,从而提高秸秆分布均匀度。The straw-soil-rotary tool interaction plays a pivotal role in the field of crop production. The simulation of straw-soil-rotary blade interaction using distinct element method（ DEM） could be hypothesized to provide a better understanding of the straw movement. Firstly,DEM model of straw-soilrotary blade interaction was established. Secondly,indoor soil bin experiments were conducted to verify simulation model,positions of straw particle at every moment were used to study straw displacement in simulation and tracer method was employed to measure straw displacement in experiments. Both simulation and experiment were performed with four rotational blade speeds（ 77 r / min,100 r / min,123 r / min,146 r / min） at constant forward speed of 0. 222 m / s and depth of 100 mm. The straw displacement both in soil bin and simulation increased with increasing rotational speed of blade.Moreover,the displacement in forward direction was larger than that of side direction at all rotational speeds in both experiment and simulation. The average error of straw displacement between simulated results and experimental results was about 40% for higher rotational speed while 70% for lower ones. Therelation equation between relative error and rotational speed can be used to predict the experimental values,and the error between the predicted ones and experimental ones were 8. 7% and 9. 3% for forward and side displacements. Microscopic movements of straws were analyzed by tracing three specific straw particles. The movement of straw near sidelong edge or lengthwise edge was affected by cutting edges,the straw located at inner side of sidelong edge slipped off along the border of sidelong edge when rotary blade started to cut the soil while the straw near lengthwise edge was pushed to move along the lengthwise edge at the initial stage of soil cutting and later was tossed upward. The movement of straw away from cutting range was only affected by soil disturbance. The straw particles near lengthwise edge or transition edge could be

关 键 词：旋耕刀 秸秆运动 离散元仿真 微观分析 

分 类 号：S222.3[农业科学—农业机械化工程]