Authors

Abstract

Aiming at the lack of discrete element simulation models and parameters for rice polishing, grading, color sorting and other technologies and equipment, and the difficulty of guiding equipment design and optimization through simulation, this paper calibrates the simulation parameters of white rice based on angle of repose (AOR) test and simulation methods. Huanghuazhan and Dongnong 429 white rice were selected as research object. Numerical model of white rice was established by multi-sphere filling. According to physical test and references, the simulation parameter range of white rice particles was determined. Plackett-Burman test was used to screen parameters, and it was found that the particle-particle static friction coefficient and particle-particle rolling friction coefficient had significant effects on the AOR of white rice. The regression model between the AOR and the significance parameter was established according to the central composite design method. The simulation parameter combination that has significant influence on the physical AOR was determined through the optimization design, and verified by the simulation test. The simulation AOR was compared with the physical AOR, and the relative error of the two kinds of white rice was less than 3%. The results show that the calibration method proposed in this study can accurately simulate the physical AOR test, which can provide reference for discrete element simulation of white rice processing.

Abstract in Chinese

针对大米加工中抛光、分级和色选等技术和装备缺乏离散元仿真模型和参数，难以通过仿真指导装备设计与优化等问题，本文基于物理堆积试验和仿真方法对白米仿真参数进行标定。以黄华占和东农429两种白米为研究对象，采用多球填充建立了白米颗粒离散元数值模型；根据物理试验和参考文献确定了白米颗粒仿真参数范围；利用Plackett-Burman试验进行参数筛选，发现颗粒-颗粒静摩擦系数、颗粒-颗粒动摩擦系数对白米堆积角影响显著；并根据中心复合试验设计方法建立了堆积角与显著性参数间回归模型；通过寻优设计确定对物理堆积角影响显著的仿真参数组合，并进行仿真试验验证，将仿真所得堆积角与物理试验值进行对比验证，两种白米的相对误差均小于3%。结果表明，该研究提出的标定方法能准确模拟物理堆积试验，可为大米加工离散元仿真提供参考。