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纳米颗粒振动床中聚团大小的计算模型

发表时间:2010-03-15  浏览量:1645  下载量:723
全部作者: 王辉,周涛,艾琼
作者单位: 中核集团北方铀业有限公司;中南大学化学化工学院
摘 要: 在内径为40 mm的振动流化床中,以纳米级SiO2为实验物料,系统考察了振动参数对纳米颗粒流化行为和聚团尺寸的影响。基于Richardson-Zaki (R-Z)方程和Stokes沉降定律,提出一个简单的数学模型并预测聚团大小。结果表明:振动能的引入可以有效地消除节涌、抑制沟流、降低最小流化速度、减小聚团尺寸,显著改善纳米颗粒的流化质量。振动强度对聚团大小的影响具有两面性,与振幅相比,振动频率对其影响较强。随着振动强度的加大,聚团尺寸的实验值和计算值均减小,在振动条件下计算值和实验值有很好的一致性。同时,随着振动强度的增加,偏析度降低。
关 键 词: 多相流反应工程;振动流化床;纳米颗粒;聚团大小;振动参数;模型
Title: Calculation model of agglomerate sizes in vibrating fluidization of nano-particles
Author: WANG Hui, ZHOU Tao, AI Qiong
Organization: North Uranium Industry Company of China National Nuclear Corporation;College of Chemistry and Chemical Engineering, Central South University
Abstract: In this study, the fluidization behavior of SiO2 nano-particles and the effects of vibration parameters on size of agglomerates have been systematically investigated in a bed of 40 mm in diameter. Base on Richardson-Zaki equation and Stokes law, a mathematical model was developed in use of studying vibrating fluidization with nano-particles. According to these experimental results slugging and channeling of bed disappeared, the minimum fluidization velocity is reduced, the measured agglomerate size is decreased and fluidization quality was significantly improved due to introduction of vibration energy. The effect of vibration on agglomeration in fluidization of nano-particles is two-sided. Compared with vibration amplitude, vibration frequency had a comparatively significant effect on agglomerates’ size. The sizes of agglomerates of the predicated values and the experimental data decreased with increasing vibration intensity, and were agreement well with each other under vibration condition. In addition, the degree of the size-segregation of the agglomerates decreased with increasing of vibration intensity.
Key words: multiphase chemical reaction engineering;vibrated fluidized bed; nano-particles; size of agglomerates; vibration parameters; model
发表期数: 2010年3月第5期
引用格式: 王辉,周涛,艾琼. 纳米颗粒振动床中聚团大小的计算模型[J]. 中国科技论文在线精品论文,2010,3(5):504-511.
 
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