基于离散元法的复合肥参数标定

Calibration of Parameters of Compound Fertilizer Based on Discrete Element Method

为解决农业肥料因物料特性与机械适配性不高的问题,改进了机械施肥作业的质量、提高了作业效率,并利用漏斗对复合肥进行了参数标定。首先,通过搭建物理试验平台测出肥料堆积角大小并测定肥料颗粒间静摩擦因数和复合肥-钢静摩擦因数;然后,用离散元仿真软件,选取Hertz-Mindlin no slip作为接触模型,以堆积角为响应值,采用Design-Expert软件设计Plackett-Burman试验,通过筛选得到对堆积角影响显著的参数,对显著参数进行最陡爬坡试验设计找到其最优范围;最后,运用Box-Behnken试验得到堆积角与各显著因素的二次回归模型,以堆积角为目标值进一步寻优,得到最优组参数解:颗粒间碰撞恢复系数0.36,颗粒间滚动摩擦因数0.19,颗粒-钢滚动摩擦因数0.16。以上述结果为试验参数进行仿真,仿真结果与物理试验结果误差分别2.48%。综上,由标定后的试验参数仿真得到的堆积角形状与物理试验的堆积角形状相似,可为机械制肥、农业施肥提供数据参考。

In order to address the problem of fertilizer blockage and leakage,the parameters of compound fertilizer were calibrated by funnel to improve the operation quality and efficiency.Firstly,the angle of repose was obtained and the static friction coefficient between particles and particle-steel static friction coefficient were determined by physical test.Subsequently,Hertz-Mindlin no slip was selected as the contact model,and the accumulation angle was used as the response value.The Plackett-Burman test was designed by Design-Expert software to select the parameters with the most significant effect on the accumulation angle.Next,seek out the optimal range of significant parameters through the steepest climbing test design.Furthermore,with the angle of repose as the response value,the Box-Behnken test was used to obtain the quadratic regression model of the angle of repose and the significant factors,and further to optimize,the optimal group solution was obtained:the collision recovery coefficient of compound fertilizer particles is 0.36,the coefficient of rolling friction between particles is 0.19,and the coefficient of rolling friction between particles and steel was 0.16.Finally,taking these results as test parameters to simulate,the errors between simulation and physical test is 1.76%.To sum up,the parameters calibration of compound fertilizer showed that the shape of the simulated accumulation angle was similar to the actual results,which could provide a reference for mechanical fertilizer production and agricultural fertilization.