不同壁面粗糙元形状对颗粒起动状态的影响  

Effect of Different Wall Roughness Element Shapes on the Incipient Motion State of Particles

作　　者：毛瑞轩 郗运柱 陈光辉[1] MAO Rui-xuan;XI Yun-zhu;CHEN Guang-hui(College of Chemical Engineering,Qingdao University of Science and Technology,Shandong Qingdao 266042,China;Shandong Juxin Chemical Technology Co.,Ltd.,Tai’an Shandong 271000,China)

机构地区：[1]青岛科技大学化工学院,山东青岛266042 [2]山东聚新化工科技有限公司,山东泰安271000

出　　处：《当代化工》2023年第5期1057-1061,1092,共6页Contemporary Chemical Industry

基　　金：山东省重点研发计划(项目编号:2021ZDSYS13)。

摘　　要：针对散堆料场颗粒扬起导致的扬尘污染问题,对散装料堆壁面附近的流场结构及颗粒起动过程进行了数值模拟。采用离散元动力学(CFD-DEM)方法分别对饼形、半球形粗糙元壁面料堆流场进行了模拟,并与光滑壁面料堆模拟结果对比。结果表明:由于粗糙元对流体的阻碍作用,粗糙元料堆壁面的流线比光滑壁面更密集;流场最大速度位于迎风面顶端,来流风速6 m·s^(-1)时,在距顶风面高度Δz=1 mm处,半球形、饼形粗糙元壁面流体最大速度分别为5.7 m·s^(-1)、5.4 m·s^(-1),均大于光滑壁面速度4.1 m·s^(-1);离壁面较远处(Δz≥2 mm)粗糙元对最大速度的影响则较小;与光滑壁面不同,在饼形与半球形粗糙元间均存在涡结构,且半球形粗糙元产生的涡结构尺度更大;上述因素导致半球形粗糙元壁面颗粒获得的起动速度远大于光滑壁面,颗粒更易起动。To address the dust pollution problem caused by particle lifting in bulk pile yard,the flow field structure and particle starting process near the bulk pile wall surface were numerically simulated.Discrete element dynamics(CFD-DEM)method was used to simulate the flow field of pie-shaped and hemispherical rough element wall pile respectively and compare with the simulation results of smooth wall pile.The results showed that the streamlines on the wall of the rough element pile were denser than those on the smooth wall,due to the obstructing effect of rough elements on the fluid.The maximum velocity of the flow field was located at the top of the windward side.When the incoming wind speed was 6 m·s^(-1),the maximum velocity of the fluid on the hemispherical and pie-shaped rough element walls was 5.7 m·s^(-1) and 5.4 m·s^(-1) respectively at the height Δz=1 mm from the top windward side,which was higher than the velocity of 4.1 m·s^(-1) on the smooth wall.Far away from the wall(Δz≥2 mm)the impact of rough elements on the maximum velocity was smaller.Different from the smooth wall,the pie-shaped and hemispherical rough elements were vortex structure,and hemispherical rough elements produced a larger scale of vortex structure.The above factors led to the hemispherical rough element wall particles to obtain much higher incipient motion speed than the smooth wall,the particles were more likely to incipient motion.

关 键 词：粗糙元 颗粒起动 流场结构 数值模拟 

分 类 号：TQ021.1[化学工程]