Authors

Abstract

Aiming at the poor efficiency in crushing a handful of caking organic fertilizers spraying from the traditional disc spreader, an improved disc spreader equipped with spike-tooth crushing unit was designed with the introduction of its structural composition and working principle. Also simulation experiments were carried out based on the discrete element method according to the solutions made before and after the structural improvement. Firstly, a granular organic fertilizer model was established based on the EDEM and a caking organic fertilizer bonding model was built based on the HMB (Hertz-Mindlin with bonding) contact model. Then two organic fertilizer spreading models corresponding to the solutions were respectively established, based on which simulation experiments were repeated three times on the spreading process. The analysis on the particle velocity vector diagram revealed the interaction relationship between organic fertilizers with the toothed shaft, external wall and disk, verifying the crushing mechanism of crushing unit. By calculating the total number of the bonds generated and broken in the spreading process in both of the spreading models, the average broken rate of bonds in the spreading process was separately 58.87% and 98.05% based on each solution, revealing that the improved solution outperformed the traditional solution in terms of the efficiency in crushing the caking organic fertilizers. This research will be a reference in designing the critical components or improving the overall performance of disc spreader.

Abstract in Chinese

针对传统圆盘式撒施机在撒施有少量结块的有机肥时，对块状有机肥破碎效果差的问题，改进设计了一种带有钉齿式破碎装置的圆盘式撒施机，阐述了其结构组成和工作原理。基于离散元法对结构改进前、后的两种方案开展模拟试验，首先用EDEM软件建立粒状有机肥模型，以Hertz-Mindlin with bonding（HMB）接触模型为基础建立块状有机肥粘结模型，然后分别建立两种方案对应的有机肥撒施模型，并对撒施过程进行三次重复模拟试验。通过对颗粒运动速度矢量图的分析，明晰了有机肥与钉齿轴、外壁、圆盘之间的作用关系，验证了破碎装置的破碎机理；通过统计两种撒施模型在撒施过程中粘结键生成总数及断裂数，计算得出两种方案在撒施过程中粘结键平均断裂率分别为58.87%、98.05%，表明改进后的方案对块状有机肥的破碎效果优于传统方案。本研究可为圆盘式撒施机关键部件设计及整机性能提升提供参考。