Effect of Schmidt number and D/d ratio on mass transfer through gas-solid and liquid-solid packed beds: Direct numerical simulations
Effect of Schmidt number and D/d ratio on mass transfer through gas-solid and liquid-solid packed beds: Direct numerical simulations
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DOI：
10.1016/j.powtec.2019.05.067
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发表时间：
2019-09
影响因子：
5.2
通讯作者：
Shivkumar Bale;S. Tiwari;K. Nandakumar;J. Joshi
中科院分区：
文献类型：
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作者：
Shivkumar Bale;S. Tiwari;K. Nandakumar;J. Joshi
研究了施密特数（Sc）和D/d比对气固和液固填料床传质的影响。研究的参数为Sc = 1、10、100和1000，Re≤ 100，D/d = 6和11，空泡率保持在0.57。进行DEM-CFD模拟以创建填充床的随机几何形状。进行了模型验证和网格独立性，并指出与实验结果吻合良好。估计填充床中每个颗粒周围的总体舍伍德数（Sho）沿着局部舍伍德数（ShL）。观察到Sho随Re增大，Sho与Re之间关系的斜率随Sc增大而增大。还报道了一个有趣的趋势，这表明Sc和D/d比对传质的综合影响。注意到，在Sc = 1时，D/d = 6的ShovsRetrend低于D/d = 11的ShovsRetrend。然而，随着Sc进一步增加，D/d = 6的趋势移动到D/d = 11的趋势之上。这种行为是由于边界效应的存在。填充床内局部舍伍德数的概率分布曲线和溶质质量分数相对于填充床轴向坐标的面积加权平均值进一步支持了这一发现。
The effect of Schmidt number (Sc) and D/d ratio on mass transfer through gas-solid and liquid-solid packed beds was studied. The parameters investigated in this study wereSc= 1, 10, 100 and 1000,Re≤ 100, D/d = 6 and 11, and the void fraction was kept constant at 0.57. DEM-CFD simulations were conducted to create the random geometry of the packed bed. Model validation and mesh independency was performed, and good agreement with the experimental results was noted. Overall Sherwood number (Sho) along with the local Sherwood number (ShL) around each particle in the packed bed was estimated. It was observed that the Shoincreases withRe, and the slope of the relationship between ShoandReincreases with increasingSc. An interesting trend was also reported, which signifies the combined effect ofScand D/d ratio on mass transfer. It was noticed that, atSc= 1, the ShovsRetrend for D/d = 6 was below the one for D/d = 11. However, asScfurther increases, the trend for D/d = 6 moves above the one for D/d = 11. This behavior is due to the presence of boundary effects. The findings were further supported by the probability distribution curves of the local Sherwood numbers in the packed bed, and the area weighted average of mass fraction of solute with respect to the axial coordinate of the packed bed.