果园四头倾斜螺旋式精准排肥器设计与试验

Design and Experiment of Four-head Inclined Spiral Precision Fertilizer Dischargers in Orchard

摘要:

针对现有传统螺旋排肥器排肥量波动大、稳定性差等问题，设计了一种四头倾斜螺旋式精准排肥器。通过运动分析和理论计算，确定了影响排肥量稳定性的主要参数及其取值范围。以螺旋叶片头数、排肥器倾角、螺旋叶片直径、螺旋叶片螺距和螺旋叶片转速为试验因素，以排肥量变异系数为试验指标，开展了单因素和多因素离散元仿真试验。单因素仿真试验结果表明，螺旋叶片头数、排肥器倾角、螺旋叶片直径和螺旋叶片转速等4个因素对排肥量稳定性有显著影响，采用四头倾斜排肥螺旋输送肥料，可以提高排肥量稳定性。多因素仿真试验结果表明，当采用四头排肥螺旋时，最优参数组合为：排肥器倾角38°、螺旋叶片直径46mm、螺旋叶片转速31 r/min。在该组合下，排肥量变异系数达到最小值，为1.65%。最后，在最优参数组合基础上，通过排肥量稳定性台架试验验证了仿真结果。结果显示，实测排肥量变异系数为 3.69%。进一步优化得到，当螺旋叶片转速为33 r/min时，排肥量变异系数达到最小值，为2.92%。仿真和台架试验表明，经过改进优化后的四头倾斜螺旋式精准排肥器在排肥稳定性方面表现良好，符合果园施肥规定标准，能够满足果园施肥作业要求。

Abstract:

To address the issues of significant fertilizer discharge fluctuations and poor stability in traditional spiral fertilizer dischargers, a four-head inclined spiral precision fertilizer discharger was designed. Through motion analysis and theoretical calculations, the key parameters affecting the stability of fertilizer discharge rate were identified, along with their optimal value ranges.Experimental factors included the number of spiral blades, discharger inclination angle, spiral blade diameter, spiral blade pitch, and spiral blade rotational speed, with the coefficient of variation of fertilizer discharge rate as the evaluation metric. Discrete element method （DEM） simulations were conducted for both single-factor and multi-factor scenarios. The single-factor simulation results indicated that the number of spiral blades, discharger inclination angle, spiral blade diameter, and spiral blade rotational speed all significantly impacted the stability of fertilizer discharge rate. It was found that using a four-head inclined spiral to convey fertilizer can enhance discharge stability. Multifactor simulation results showed that the optimal parameter combination for a four-head spiral configuration was with discharger inclination angle of 38°，spiral blade diameter of 46 mm, and spiral blade rotational speed of 31 r/min. Under this combination, the coefficient of variation of fertilizer discharge rate reached minimum value of 1.65%. Finally, bench tests were conducted to validate the simulation results under the optimal parameter combination. The tests revealed that the measured coefficient of variation for fertilizer discharge rate was 3.69%. Further optimization determined that at spiral blade rotational speed of 33 r/min, the coefficient of variation could be minimized to 2.92%. Both simulation and bench test results demonstrated that the improved four-head inclined spiral precision fertilizer discharger performed well in terms of fertilizer discharge stability, which can meet orchard fertilization standards, and satisfy the operational requirements for orchard fertilization.