贮料重度对卸料流态及仓壁压力分布的影响  

Influences of gravity density on discharge flow pattern and pressure distribution along silo walls

作　　者：刘克瑾 黄硕硕 姚辉江 贾玲玲[1] 谢双臣 LIU Kejin;HUANG Shuoshuo;YAO Huijiang;JIA Lingling;XIE Shuangchen(College of Civil Engineering and Architecture,Henan University of Technology,Zhengzhou 450001,China)

机构地区：[1]河南工业大学土木工程学院,郑州 450001

出　　处：《农业工程学报》2024年第15期44-53,共10页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金资助项目(51708183);河南工业大学高层次人才基金项目(31400375);河南工业大学创新基金支持计划专项资助项目(2022ZKCJ07)。

摘　　要：为了研究贮料重度对仓壁卸料压力和流态的影响,该研究进行了室内试验和数值模拟分析。室内试验采用自主设计的半圆柱形平底圆筒仓,仓壁嵌入定制的压力传感器量测仓壁压力,通过摄像机记录流态演化过程。贮料选用重度不同平均粒径为5.5 mm的陶球颗粒(以下简称陶粒)和大豆,各进行了5组卸料试验。并进行了离散元(discrete element method,DEM)数值模拟。最后,综合试验结果和数值模拟结果,结合颗粒物质力学基本原理,分析了贮料重度对流态演化及仓壁压力分布的影响。结果表明:陶粒和大豆的流态演变过程相似;静止区边界在卸料前期和中期处于稳定状态,贮料静止区角度为54.03°,高度为0.310 m,卸料后期,表面流动边界面开始与静止区边界面以28.5°相交,并最终滞留在仓底附近形成角度为28.5°,高度为0.120 m的“滞留区”;贮料重度越大,仓壁压力变化越剧烈;峰值压力作用点在距离仓壁底部约3/10高度处;在卸料最初(卸料时间5 s,占总卸料时长的1.43%),陶粒和大豆的仓壁压力均发生剧烈突增:陶粒峰值增幅为263%,大豆峰值增幅为257%,该现象为实践中筒仓破坏多出现在卸料初期提供了试验支持。基于细观层面的力链网络演化,证实了重度大的陶粒通过力链网络传递到仓壁的压力更大,仓壁压力波动性与力链的断裂、重构和结拱起始、结拱完成和拱塌落有直接的对应关系。研究建立了从细观力链网络传递、力链断裂、重构与宏观仓壁压力分布的直接联系,研究结果可为筒仓结构设计提供理论支撑与试验依据。This study aims to investigate the impact of gravity material density on wall pressure and flow patterns during silo discharge using indoor tests and numerical simulations.A self-developed semi-cylindrical flat-bottomed circular silo was utilized in the indoor tests.The custom pressure sensors were embedded in the silo walls to measure the wall pressure.The cameras were used to record the evolution of flow patterns.Two types of gravity materials were selected with different densities and an average particle size of 5.5 mm:ceramic balls(referred to as ceramic particles)and soybeans.Five discharge tests were then conducted on each material.Subsequently,discrete element method(DEM)numerical simulations were performed to supplement the test observations.The experimental and numerical simulations were combined to explore the effects of gravity material density on the flow pattern and wall pressure.The results reveal that there was a similar flow evolution of ceramic particles and soybeans,indicating the transitions from the mass,funnel,and mixed flow to the tubular flow.There was a dynamic variation in the boundary between the flowing and stationary zones during discharge.The boundary of the stationary zone remained stable at the early and middle stages of discharge,with an angle of 54.03°and a height of 0.310 m.In the late stage of discharge,the flowing boundary on the surface of the gravity material was intersected with the stationary zone boundary at an angle of 28.5°,ultimately forming a"detention zone"near the bottom of the silo with an angle of 28.5°and a height of 0.120 m.The density of the gravity material then dominated the fluctuation of wall pressure.The materials with the higher gravity density caused the more intense variations in the pressure on the silo wall.Among them,the ceramic particles shared a greater pressure amplitude than the soybeans.There was no influence of gravity material density on the location of the peak lateral pressure.The peak points of lateral pressure for both ceramic particles

关 键 词：筒仓 散体材料 流态 离散元法 力链网络 卸料压力 卸料试验 重力密度 

分 类 号：S126[农业科学—农业基础科学]