Analysis of the effect of small amounts of liquid on gas–solid fluidization using CFD‐DEM simulations
Analysis of the effect of small amounts of liquid on gas–solid fluidization using CFD‐DEM simulations
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DOI：
10.1002/aic.15819
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发表时间：
2017-12
期刊：
影响因子：
3.7
通讯作者：
C. Boyce;A. Ozel;J. Kolehmainen;S. Sundaresan
中科院分区：
文献类型：
--
作者：
C. Boyce;A. Ozel;J. Kolehmainen;S. Sundaresan
使用CFD-DEM模型模拟了涉及少量液体的气固流化。该模型跟踪每个颗粒和壁面单元上的液体量，并结合颗粒之间的液体传输和在两个颗粒之间以及颗粒和壁面单元之间形成的摆式液体桥的有限速率。模拟了由这些桥引起的粘性力和毛细力。流态化-脱流化曲线表明，由于内聚和非均匀流动结构，最小流态化速度和脱流床高度随着键数（Bo）、表面张力与重力之比的增加而增加。在流态化条件下，流体力学和液体桥接行为随Bo的增加而发生显著变化，而随毛细管数、粘性与表面张力之比的变化程度较小。当在湿润条件下保持表面流速与最小流化速度的恒定比时，床层流动性在湿润条件下保持相对恒定。©2017美国化学工程师学会化学工程学报，63:5290-5302,2017
Gas–solid fluidization involving small amounts of liquid is simulated using a CFD-DEM model. The model tracks the amount of liquid on each particle and wall element and incorporates finite rates of liquid transfer between particles and pendular liquid bridges which form between two particles as well as between a particle and a wall element. Viscous and capillary forces due to these bridges are modeled. Fluidization–defluidization curves show that minimum fluidization velocity and defluidized bed height increase with Bond number (Bo), the ratio of surface tension to gravitational forces, due to cohesion and inhomogeneous flow structures. Under fluidized conditions, hydrodynamics and liquid bridging behavior change dramatically with increasing Bo, and to a lesser extent with capillary number, the ratio of viscous to surface tension forces. Bed fluidity is kept relatively constant across wetting conditions when one maintains a constant ratio of superficial velocity to minimum fluidization velocity under wet conditions. © 2017 American Institute of Chemical Engineers AIChE J, 63: 5290–5302, 2017