气力集排式精量配混施肥装置设计与试验

为满足玉米生长中后期的追肥需求，本文设计一种气力集排式精量配混施肥装置。电机驱动叶片旋转进行混肥，将肥料分配器内部设计成锥形结构。基于流体动力学和离散元耦合法对分配器排肥口倾角、分配器上端波纹管的结构和布置方式进行研究；以排肥口倾角、输送气速和波纹管长度为试验因素，以各行排肥量变异系数为试验指标，进行三元二次回归正交组合设计试验。试验结果表明，当排肥口倾角45°、输送气速35m/s、波纹管长度568mm时，性能最优。混肥器进口采用中心布置方式，叶片数量为8。田间试验结果表明，该机施肥量误差小于2%，总施肥量稳定性变异系数为2%，施肥断条率低于2%，满足国家标准。

Design and Experiment of Pneumatic Aggregate and Discharge Precision Fertilizer Mixing Device

In order to meet the requirement of top dressing in the middle and late period of maize growth, a kind of pneumatic gathering and discharging type corn precision fertilizer mixing device was designed. The variable mixing fertilizer scheme with pneumatic set and row was designed. The motor driven blade rotation was used to mix fertilizer, and the inside of the fertilizer distributor was designed as a cone structure. By means of computer fluid dynamics, discrete element coupling method and two factors and five levels orthogonal experiment, the dip angle of the fertilizer outlet and the structure and arrangement of the bellows at the upper end of the distributor were studied. With the coefficient of variation of fertilizer discharge in each row as the test index, and with the angle of fertilizer discharge outlet, conveying gas velocity, and bellows length as the experiment factors, a three-way quadratic regression orthogonal combination design experiment was conducted to obtain the optimal operation parameters of key components of the precision fertilizer mixing device, namely, the angle of fertilizer discharge outlet of 45°, conveying gas velocity of 35m/s, and bellows length of 568mm. The inlet layout of fertilizer mixer was as follows: central layout, and the number of blades was 8. In June 2019, the machine field inspection was done at the National Agricultural Machinery and Tools Quality Supervision and Inspection Center, the inspection results showed that the machine''s fertilizer application error was 2%, the total fertilizer application stability coefficient was 2%, and the fertilization rate was less than 2%. The research result can provide useful reference for the design and development of pneumatic fertilizing machinery and tools.