离心腔盘挤出式油菜高速精量排肥器设计与试验

Design and experiment of a centrifugal cavity disc extrusion typehigh-speed precision fertilizer apparatus for rapeseed

针对现有排肥装置无法满足油菜高速机直播排肥量范围且易卡顿拥堵,排肥稳定性差及肥料颗粒破碎严重的问题,该研究设计了一种离心腔盘挤出式油菜高速精量排肥器。根据高速直播作业农艺要求,结合肥料颗粒运动过程分析,确定了进肥口、离心腔盘、排肥口、动力系统等关键参数。利用离散元软件EDEM建立排肥过程仿真模型,明确了排肥器转速变化对离心腔盘转矩、肥料颗粒平均载荷、肥料破碎率的影响规律。分析结果表明,随着排肥器转速增加,离心腔盘转矩增加,腔盘内的肥料颗粒平均载荷逐渐减小,破碎率增加,破碎率不超过0.80%。排肥器性能试验表明,排肥器转速30~120 r/min(对应排量15.0~58.1 g/s),可满足最大施肥量为600 kg/hm^(2)时3.0~12.0 km/h的油菜高速机直播作业需求,排肥器各行排量一致性变异系数低于8.58%,同行排量稳定性变异系数低于6.45%,破碎率低于0.89%;正常田间作业0°~5°倾斜状态下各行排量一致性变异系数不超过8.72%。对比试验结果表明,相较螺旋扰动式排肥器,离心腔盘式排肥器适应高速作业,破碎率减少63.82%,高速大排量排肥时未出现卡肥堵塞等情况。田间试验表明,作业速度在4.1~10.1 km/h范围内,排肥器各行排量一致性变异系数不大于6.72%,同行排肥量稳定性变异系数不大于4.84%,实际排肥量相对误差小于4.54%。设计的排肥器排量范围广,排肥顺畅稳定,破碎率低,满足油菜高速直播精量排肥需求。

Precision fertilization is one of the key technologies to control non-point source pollution in agriculture.Fertilizer reduction and efficiency technology can greatly contribute to green and sustainable agriculture in the rice-oil rotation region in the mid-lower reaches of the Yangtze River.Among them,fertilizer apparatus s have been focused mainly on the performance and optimization of structural devices.It is relatively lacking in the high speed and precision of fertilizer apparatus for rapeseed in real time.It is a high demand to optimize the precision fertilizer discharging for the reference value.The performance of fertilizer apparatus can depend directly on the accuracy of working components,in terms of uniformity and rational fertilization.However,the existing fertilizer apparatus cannot fully meet the range of direct seeding rapeseed of high-speed machines,due to the jam,low stability and distribution,as well as the serious crushing of particle fertilizer.In this study,an extrusion fertilizer apparatus for rapeseed was designed with a centrifugal cavity disc with high speed and precision.According to the agronomic requirements of high-speed direct seeding,the movement analysis of fertilizer particles was combined to determine the key parameters,such as fertilizer inlet,centrifugal cavity disc,fertilizer outlet,and power system.The discrete element software(EDEM)was used to establish the simulation model of fertilizer discharging.A systematic investigation was implemented to clarify the influence of the speed of the fertilizer apparatus on the torque of the centrifugal cavity disc,the average load,and the crushing rate of fertilizer particles.The results showed that the torque of the centrifugal cavity disc increased,whereas,the average load of fertilizer particles in the cavity disk decreased gradually,and the crushing rate increased below 0.80%,with the increase of the speed of fertilizer apparatus.The performance test showed that the speed of the fertilizer ejector was 30-120 r/min,and the displacement was 15.0-58.1 g/s,fully meeting the demand of high-speed direct seeding when the maximum fertilization amount was 600 kg/hm^(2).The coefficient of variation was less than 8.58%for the consistent displacement in each row of fertilizer discharging,less than 6.45%for the stability of the displacement in the same industry,and the crushing rate was less than 0.89%;Specifically,the coefficient of variation was below 8.72%for the displacement consistency of each row shall under normal field operation with 0°~5°inclination.The comparative test showed that compared with the spiral perturbation,the fertilizer discharging with a centrifugal cavity disc was suitable for high-speed operation,where the crushing rate was reduced by 63.82%.There was no fertilizer jam when discharging fertilizer at high speed and large displacement.The field test showed that when the operation speed was in the range of 4.1-10.1 km/h,the coefficient of variation was not more than 6.72%for the consistent discharge in each row of the fertilizer ejector,while the coefficient of variation for the stability of the same row during fertilizer discharging was not more than 4.84%,and the relative error between actual and theoretical fertilizer discharging was less than 4.54%.The fertilizer discharging shared a wide range of displacement,smooth and stable operation,in order to effectively avoid the fertilizer sticking and the crushing rate in the process of fertilizer discharging.The fertilizer apparatus also fully met the demand for the high-speed direct seeding and precision fertilizer discharging of rapeseed.