CFD-DEM modeling the effect of column size and bed height on minimum fluidization velocity in micro fluidized beds with Geldart B particles
CFD-DEM modeling the effect of column size and bed height on minimum fluidization velocity in micro fluidized beds with Geldart B particles
复制标题
DOI：
10.1016/j.powtec.2017.06.020
复制
发表时间：
2017-08
影响因子：
5.2
通讯作者：
Yupeng Xu;Tingwen Li;Jordan Musser;Xiaoxing Liu;Guangwen Xu;W. Rogers
中科院分区：
文献类型：
--
作者：
Yupeng Xu;Tingwen Li;Jordan Musser;Xiaoxing Liu;Guangwen Xu;W. Rogers
利用计算流体动力学和离散元法（CFD-DEM）对Geldart B颗粒在微流化床中的流态化行为进行了数值研究。考察了不同床层内径(D)为8 mm、12 mm、16 mm和不同初始静床高(H)的影响。研究发现，在微流化床中，减小塔径和增大床高均可提高最小流化速度（Umf）。在流化开始前所观察到的压降超调量随着塔径的增大而减小，但对床层高度的敏感性较小。总的来说，数值结果与已有的理论关联和实验研究定性一致。模拟结果表明，柱径和颗粒壁面摩擦力对最小流化速度的变化都有影响。这两个因素是相互关联的，很难分开。在规定柱径为8mm的条件下，壁面摩擦力在0 ~ 0.4范围内变化，研究了壁面摩擦力对最小流化速度的影响。
The fluidization behavior of Geldart B particles in micro fluidized beds is investigated numerically using Computational Fluid Dynamics coupled with Discrete Element Method (CFD-DEM) available in the open-source Multiphase Flow with Interphase eXchanges (MFIX) code. The effects of different bed inner diameters (D) of 8 mm, 12 mm, 16 mm and various initial static bed heights (H) were examined. It is found that both decreasing the column diameter and increasing the bed height in a micro fluidized bed increases the minimum fluidization velocity (Umf). The observed overshoot in pressure drop that occurs before the onset of fluidization decreases in magnitude with increasing column diameter, however there is less sensitivity to bed height. Overall, the numerical results agree qualitatively with existing theoretical correlations and experimental studies. The simulations show that both column diameter and particle-wall friction contribute to the variation in minimum fluidization velocity. These two factors are coupled and hard to separate. The detailed influences of wall friction on minimum fluidization velocity are then investigated for a prescribed column diameter of 8 mm by varying the wall friction from 0 to 0.4.