摘要
利用氢氧焰燃烧合成的纳米二氧化硅颗粒,研究了其自发团聚现象及流化过程中的二次团聚行为,考察了流化床床层压降随操作气速和温度的变化,以及颗粒表面能及热处理温度对起始流化速度的影响。结果表明:在范德华力等粘性力作用下,纳米二氧化硅颗粒形成团聚体,团聚体粒度随二氧化硅颗粒表面吸附水分的增多而增大;纳米二氧化硅颗粒在流化过程中,一次团聚体在流体力作用下进一步团聚形成二次团聚体;流化停止后二次团聚体解体,此时纳米二氧化硅的团聚行为与流化前无明显差异;热处理温度对纳米二氧化硅颗粒起始流化速度影响不大,但纳米二氧化硅颗粒的起始流化速度随颗粒表面能的减小而显著降低,而且颗粒的表面处理对床层塌落与膨胀行为具有重要影响。
By the use of silica nanoparticles synthesized by H2/Air flame combustion, the agglomeration behaviors and fluidized properties of silica nanoparticles were studied at different conditions. The results indicate that spontaneous agglomerates are easily formed because of Van der Waals force, etc, and the size of agglomerates increase with increasing amount of moisture absorbed on the surface of silica nanoparticles. Fluid-dynamic agglomerated are formed when silica nanoparticles are fluidized in the bed. The initial fluidizing gas velocity decreases with increasing of temperature and with decreasing of surface energy of silica nanoparticles. The collapse and expanding behavior is strongly affected by the modification of silica nanoparticles.
出处
《华东理工大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2005年第2期163-167,共5页
Journal of East China University of Science and Technology
基金
国家自然科学基金(20236020
20176009)
上海市基础研究重大项目(04DZ14002)
教育部<跨世纪优秀人才培养计划>
上海市纳米科技基金项目等资助
