Authors

Abstract

This study aimed to optimize the critical parameters of an grooved wheel fertilizer distributor for precision application of granular organic fertilizer. The variation coefficient of fertilization uniformity was used as the evaluation index. The fertilizer applicator model was developed in SolidWorks®. The model of organic fer-tilizer particles was established using 3D scanning technology. Using a texture analyzer, the Poisson's ratio of the fertilizer was determined to be 0.314, and the elastic modulus was 9.8×10^7 Pa. The drop test results showed the fertilizer’s collision recovery coefficients with fertilizer, PA, PC, and PLA were 0.422, 0.436, 0.426, and 0.421, respectively. The inclined plane rolling test showed the fertilizer’s rolling friction coeffi-cients with PA, PC, and PLA were 0.156, 0.154, and 0.157, respectively. The cylinder lifting test of repose angle, EDEM software simulation, and Design-Expert software experimental design helped determine the static friction coefficient between fertilizer and fertilizer as 0.413 and the dynamic friction coefficient between fertilizer and fertilizer as 0.181. The static friction coefficient between the fertilizer and PA, PC, and PLA was 0.276, 0.266, and 0.173, respectively. The optimal structural and operational parameters were obtained by combining the Discrete Element Method (DEM) and Response Surface Methodology (RSM). The grooved wheels with different structural parameters were 3D printed and soil bin tests were performed to verify the simulation results. The results showed that the variation coefficient of fertilization uniformity was minimal when the incircle diameter of grooved wheel was 37 mm, the number of grooves was 7, and the lead angle of grooved wheel was 63°. When the effective working length of grooved wheel was 31 mm, the fertilizer shaft speed was 28 RPM, the fertilizer discharge flap angle was -1°, the variation coefficient of fertilization uniformity was the minimum.

Abstract in Chinese

针对外槽轮式排肥器施用颗粒有机肥关键参数优化问题，本文以排肥均匀性变异系数为评价指标，应用SolidWorks软件，建立排肥器模型；应用3D扫描技术，建立有机肥颗粒模型；通过三轴尺寸测量，获得肥料等效直径为4.29mm，球形率为97%；通过质构仪，获得肥料泊松比为0.314，弹性模量为9.8×10^7Pa；针对排肥器部件的三种不同材料，通过下落试验，获得肥料与肥料、PA、PC、PLA的碰撞恢复系数分别为0.422、0.436、0.426、0.421；通过斜面滚动试验，获得肥料与PA、PC、PLA的滚动摩擦系数分别为0.156、0.154、0.157；通过休止角圆筒提升试验、EDEM软件仿真，结合Design-Expert软件试验设计，测定肥料-肥料静摩擦系数为0.413，肥料-肥料动摩擦系数为0.181，肥料与PA、PC、PLA的静摩擦系数分别为0.276、0.266、0.173。以排肥器结构参数、工作参数为试验因素，综合应用离散元法、正交试验法，开展了EDEM仿真单因素、多因素试验。采用3D打印不同结构参数的槽轮，设置对应工作参数，开展土槽试验，验证了仿真结果。结果表明，结构参数槽轮内接圆直径37mm、凹槽数目7个、槽轮升角63°时，排肥均匀性变异系数最小；工作参数有效工作长度31mm、排肥轴转速28r/min、排肥舌角度为－1°时，排肥均匀性变异系数最小。