稻谷颗粒物料堆积角模拟预测方法  

Simulation prediction method of repose angle for rice particle materials

作　　者：贾富国[1] 韩燕龙[1] 刘扬[1] 曹银平[1] 史宇菲[1] 姚丽娜[1] 王会[1] 

机构地区：[1]东北农业大学工程学院,哈尔滨150030

出　　处：《农业工程学报》2014年第11期254-260,共7页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家"十二五"科技支撑计划项目(2012BAD34B0205-2);黑龙江省自然科学基金资助项目(E201322);哈尔滨市优秀学科带头人基金(RC2013XK006004);黑龙江省科技攻关项目(GC12B404)

摘　　要：为了准确预测颗粒物料的堆积角,研究采用数值仿真方法对堆积状态的颗粒物料进行模拟预测。以稻谷颗粒物料为例,应用离散元法和MATLAB图形图像处理技术,模拟了稻谷在无底圆筒中落料堆积现象,并对堆积图像轮廓采取线性拟合,在非试验条件下预测出稻谷堆积角,预测堆积角为22.66°±0.49°,与实际堆积试验比较,试验堆积角为22.62°±0.33°,误差为0.18%。结果表明:数值模拟结合图像特征提取的方法对稻谷颗粒物料堆积角的测量有较好的适用性,能实现对已知物理及力学参数的椭球形颗粒物料堆积角的预测,研究的结果可为农业散体非规则形籽粒堆积角的数值测量提供参考。Angle of repose is an important macroscopic feature in characterising the interactions within an assembly of particles. In order to accurately predict the angle of repose of the particle material,a numerical simulation study was applied on the process of particle packing based on discrete element method. In this paper, a simulation model of bottomless cylinder was designed with EDEM software. By taking the rice particles as the example, the physical properties of rice particles, including density, Poisson’s rate, shear modulus, coefficient of restitution, coefficient of static fraction, and coefficient of rolling fraction were obtained through the study of some scholars. The shape of rice particle was regarded as ellipsoid. The average value of rice particles’ dimension parameters were reported in statistics, namely the long axis is 7.2 mm, and the minor axis is 3.0 mm. According to the shape and the dimension parameters of rice particles, a method for establishing the model of particle based on particles agglomerate was employed, and with the 9 spherical particles agglomerate to approximate real shape grain. In the process of simulation, the cylinder was firstly filled with rice particles. Based on the number and density of particles, the average mass of 43.12 g was calcuated. After being filled with the particles, the cylinder was slowly lifted at a speed of 0.05m/s. Particles flowed from the mouth of the cylinder and formed a stable accumulation under gravity load. In addition, this paper analysed the influence of different lifting speed on the accumulation form.The numerical results showed that, under identical conditions, increasing lifting speed of cylinder led to the rise in diffusion trend of the edge of the grain heap particles. However, when the speed was less than 0.07 m/s, granular pile was formed relatively stably. Meanwhile, this paper obtained the unilateral outline of particle accumulation through MATLAB image processing technology. Then linear fitting was applied to process image contour of r

关 键 词：图像处理 数值方法 模型 颗粒物料 堆积角 离散元 预测 

分 类 号：O347.7[理学—固体力学] TP391.9[理学—力学]