飞灰在单纤维上形成颗粒链的生长和形貌  

Growth and morphosis of particle chains during fly ash loading on a single fiber

作　　者：黄斌[1] 姚强[1] 赵海亮[1] 宋蔷[1] 由长福[1] 

机构地区：[1]清华大学热能工程系热科学与动力工程教育部重点实验室,北京100084

出　　处：《清华大学学报（自然科学版）》2006年第5期662-665,共4页Journal of Tsinghua University(Science and Technology)

基　　金：国家"九七三"重点基础研究项目(2002CB211600)

摘　　要：为了深入研究静电对纤维滤料过滤过程的影响,利用显微镜与CCD摄像技术,实时观测对比了体积平均直径为1.4μm飞灰颗粒在自然、极化和荷电条件下,被直径为20μm的单纤维捕集的过程。自然条件下,迎风面颗粒沉积形成“灌木丛”状颗粒链,并按照纤维捕捉、纤维和颗粒链共同捕捉与颗粒链单独捕捉3个阶段持续增长;背风面初始阶段形成4μm左右的链后便停止增长。极化条件下,形成分叉较少的直链,并具有10μm左右的较均匀间距,直链在平均链长20μm左右开始倒伏;倒伏并顺风拖曳在纤维背风向的长链仍具有较强的颗粒捕捉能力。荷电条件下,虽也能形成直链,但其分布相对不均匀,具有一些分叉;当平均长度为10μm左右颗粒链开始倒塌和断裂,倒塌于迎风面的颗粒链减弱了继续形成直链的能力。The deposit of 1.4 μm fly ash particles on a single 20μm fiber with pretreatment conditions was observed with a microscope and CCD to study the effect of electrostatics in fibrous filtration. The results show that tribo-charged particles form many dendrites on the upstream surface, but the dendrites stop growing on the downstream side when they are about 4 μm long. Polarized particles form chains at 10μm intervals and collapse when their mean heights reach about 20 μm, but these collapsed chains still capture many particles. Pre-charged particles form chains with some branches which collapse and break when their mean heights reach about 10μm. After these chains collapse on the fiber surface, new chains do not readily form.

关 键 词：显微镜 单纤维 过滤 颗粒链 静电 形貌 

分 类 号：TK284.5[动力工程及工程热物理—动力机械及工程] X5[环境科学与工程—环境工程]