Structure of packed beds probed by Magnetic Resonance Imaging
Structure of packed beds probed by Magnetic Resonance Imaging
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DOI：
10.1016/s0032-5910(00)00374-0
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发表时间：
2001-06
影响因子：
5.2
通讯作者：
A. Sederman;P. Alexander;L. Gladden
中科院分区：
文献类型：
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作者：
A. Sederman;P. Alexander;L. Gladden
磁共振成像（MRI）体积可视化与图像分析技术相结合，用于表征柱与颗粒直径比为9，14和19的未固结和固结的球蛋白填充床的颗粒间空间内的结构。床的特点是使用两种方法。首先，计算空隙率的径向分布。在垂直于床的轴的平面中的空隙空间的减少的径向分布函数也用于调查空隙空间内的相关结构。对于所有的柱-颗粒直径，相关的结构延伸到6.5直径的填充材料，并被认为是增加固结。其次，颗粒间空间被分割成单独的孔，其被定义为由固体表面和竖立的平面界定的空隙空间的一部分，其中空隙空间的水力半径表现出局部最小值。统计分布的这些孔的特征，如半径，表面积，体积和协调其他孔，得到。在固结时，存在小孔数量的增加和孔隙空间内收缩的相对尺寸的减小。床的详细孔隙结构的这种显著变化将沿着总孔隙度的降低，也在固结时观察到，以产生一种结构，这将影响与床相关的特征流体动力学。
Magnetic Resonance Imaging (MRI) volume-visualisation in combination with image analysis techniques are used to characterise the structure within the inter-particle space of unconsolidated and consolidated packed beds of ballotini for column-to-particle diameter ratios of 9, 14 and 19. The beds are characterised using two approaches. First, radial distributions of the voidage are calculated. The reduced radial distribution function of the void space in a plane perpendicular to the axis of the bed is also used to investigate correlated structures within the void space. For all column-to-particle diameters, the correlated structure extends up to 6.5 diameters into the packing material and is seen to increase upon consolidation. Second, the inter-particle space is segmented into individual pores, defined as a portion of the void space bounded by a solid surface and planes erected where the hydraulic radius of the void space exhibits local minima. Statistical distributions of the characteristics of these pores, such as radius, surface area, volume and coordination to other pores, are obtained. Upon consolidation, there is an increase in the number of small pores and decrease in the relative size of constrictions within the pore space. This significant change in the detailed pore structure of the bed will act along with the decrease in overall porosity also observed upon consolidation to create a structure, which will influence the characteristic hydrodynamics associated with the bed.