CFD–DEM modeling of gas fluidization of fine ellipsoidal particles
CFD–DEM modeling of gas fluidization of fine ellipsoidal particles
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DOI：
10.1002/aic.15050
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发表时间：
2016
期刊：
影响因子：
3.7
通讯作者：
J. Gan;Zongyan Zhou;A. Yu
中科院分区：
文献类型：
--
作者：
J. Gan;Zongyan Zhou;A. Yu
颗粒特性是影响气体流化的重要因素。本文采用计算流体动力学与离散元相结合的方法，研究了不同流态下颗粒尺寸和形状对流态化的影响。首先从流态和流态化参数如压降、最小流态化和鼓泡速度等方面对结果进行了分析。结果表明：随着颗粒尺寸的减小，细小的椭球状颗粒可形成团聚体；特别是“链式现象”，这是由范德华力引起的一种特殊的凝聚现象，它存在于膨胀床和流化床中。最小流化速度随粒径的增大呈指数增长，在一定粒径下，随长径比呈“W”形。建立了最小流化速度与颗粒大小和形状的关系。椭球具有更高的最小鼓泡速度和流化指数。©2015美国化学工程师学会化学工程学报，62:62 - 77,2016
Particle characteristics are important factors affecting gas fluidization. In this work, the effects of both particle size and shape on fluidization in different flow regimes are studied using the combined computational fluid dynamic–discrete element method approach. The results are first analyzed in terms of flow patterns and fluidization parameters such as pressure drop, minimum fluidization, and bubbling velocities. The results show that with particle size decreasing, agglomerates can be formed for fine ellipsoidal particles. In particular, “chain phenomenon,” a special agglomerate phenomenon exists in expanded and fluidized beds for fine prolate particles, which is caused by the van der Waals force. The minimum fluidization velocity increases exponentially with the increase of particle size, and for a given size, it shows a “W” shape with aspect ratio. A correlation is established to describe the dependence of minimum fluidization velocity on particle size and shape. Ellipsoids have much higher minimum bubbling velocities and fluidization index than spheres. © 2015 American Institute of Chemical Engineers AIChE J, 62: 62–77, 2016