【摘要】 针对合理耕层构建技术指标要求,设计了气力式秸秆深埋还田机输送装置。其主要结构参数为:输送管截面为0. 2 m×0. 2 m方形管;叶轮直径为0. 55 m,叶轮宽度为0. 17 m,进气口直径为0. 26 m,风机壳宽度为0. 2 m;螺旋轴直径为0. 09 m,螺旋叶片外径为0. 25 m,螺距为0. 2 m,螺旋叶片厚度为0. 003 m,螺旋外径与输送管内表面间隙为0. 005 m。通过玉米悬浮速度试验测得,长度为10 cm玉米秸秆上、中、下部分悬浮速度分别为10. 4、12. 3、12. 7 m/s,平均值为11. 9 m/s,试验结果与仿真误差为7%。基于气固耦合理论,通过CFD-DEM气固耦合法对输送装置内的气固两相流模拟研究,表明弯角30°、转速为1 800 r/min时输送管道中,秸秆最小速度为5. 21 m/s,所对应的气流速度为17～27 m/s,出口处玉米秸秆速度为6. 06 m/s,气流速度为2～27 m/s,秸秆输送效果最佳。田间试验结果表明,气力输送装置性能参数最优组合为:风机转速1 800 r/min,秸秆覆盖量1. 2 kg/m2,叶片弯角30°。田间验证试验得深埋合格率为93. 2%,有效提高了深埋质量。更多还原

【Abstract】 The pneumatic style straw deep burying and returning machine enjoys comprehensive functions in the aspect of stubble breaking,straw picking and crushing,ditching and crushing,inter-row deep loosening,deep-buried straw,soil covering,and finally buries the straw below 20 cm between rows and at the same time constructs the furrow loose and ridge compaction plough layer structure. According to the technical requirements of reasonable tillage construction,the pneumatic conveying device was designed.The main structural parameters of the conveying device were as follows: the cross section of the conveying pipe was 0. 2 m × 0. 2 m square pipe; the impeller diameter was 0. 55 m; the width of impeller was0. 17 m; the inlet diameter was 0. 26 m; the width of fan shell was 0. 2 m; the outer diameter of screw blade was 0. 25 m; the diameter of the screw shaft was 0. 09 m; the screw pitch was 0. 2 m; the thickness of the screw blade was 0. 003 m; and the clearance between the outer diameter and the inner surface of the conveying pipe was 0. 005 m. According to the test of suspended velocity for corn,the suspended velocity of upper,middle and lower parts of 10 cm corn stalk was 10. 4 m/s,12. 3 m/s and 12. 7 m/s,respectively,with an average of 11. 9 m/s. The test results and simulation error was 7%. On the basis of gas-solid coupling theory,the CFD-DEM method was used to simulate the two-phase flow of gas-solid in the conveyor. When the angle was 30° and rotation speed was 1 800 r/min,the minimum velocity of straw in the conveying pipeline was 5. 21 m/s. And the corresponding velocity of air flow was 17 ～ 27 m/s. At the outlet,the velocity of straw reached 6. 06 m/s,and 2 ～ 27 m/s at the air flow rate. The number of straw inside the fan was 24 at 1. 2 s,and then it had the most effective delivery. The results of field experiment showed that the optimum combination of performance parameters of pneumatic conveyor was asfollows: blade bending angle was 30°,straw coverage was 1. 2 kg/m2,fan speed was 1 800 r/min and the qualified rate of deep-buried was 93. 2%. The research had effectively improved the deep-buried quality and also can provide reference on further study on performance improvement of pneumatic straw deep burying and returning machine as well as the promotion of agriculture mechanization level.更多还原