Abstract The hydrodynamic behavior of a bubbling gas-solid fluidized bed with vertically immersed membrane tubes has been studied using an endoscopic-laser PIV/DIA technique. The solids mass flux and hold-up profiles were determined together with the bubble phase properties (equivalent bubble diameter and bubble rise velocity) for different operating conditions and different membrane bundle configurations. The obtained results revealed that the lateral solids motion can be significantly hampered due to the presence of the membrane tubes resulting in a very high solids hold-up near the walls and much diluted regions in the middle of the bed. The obtained results from the experiments with a different number of membranes, membranes with a different outer diameter, and positioned with the bottom of the bundle at different axial positions in the bed, give guidelines to optimize the membrane configurations to achieve the highest lateral gas dispersion and optimal bubble breakage. These experimental results have also demonstrated the very important effect of tube spacers on the hydrodynamics. Moreover, the analysis of the bubble phase properties confirmed the enormous decrease in equivalent bubble diameter (up to a factor 3.5) for fluidized beds with immersed vertical membranes with spacers in comparison with a fluidized bed without internals, showing the great potential for improvement of the bubble-to-emulsion phase mass transfer rate. This work has been selected by the Editors as a Featured Cover Article for this issue.

中文翻译：

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使用内窥镜激光 PIV/DIA 技术研究具有浸没式垂直膜的致密气固流化床的流体动力学

摘要 使用内窥镜激光 PIV/DIA 技术研究了带有垂直浸入式膜管的鼓泡气固流化床的流体动力学行为。对于不同的操作条件和不同的膜束配置，固体质量通量和滞留率曲线与气泡相特性（等效气泡直径和气泡上升速度）一起确定。获得的结果表明，由于膜管的存在，会显着阻碍横向固体运动，从而导致壁附近的固体滞留量非常高，床中间的区域被稀释得很多。使用不同数量的膜、具有不同外径的膜以及将束底部定位在床中不同轴向位置的实验获得的结果，给出优化膜配置的指南，以实现最高的横向气体扩散和最佳的气泡破裂。这些实验结果也证明了管间隔件对流体动力学的非常重要的影响。此外，气泡相特性的分析证实，与没有内部构件的流化床相比，带有隔板浸入式垂直膜的流化床的等效气泡直径显着降低（高达 3.5 倍），这显示了改进的巨大潜力气泡到乳液相的传质速率。这项工作已被编辑选为本期的特色封面文章。这些实验结果也证明了管间隔件对流体动力学的非常重要的影响。此外，气泡相特性的分析证实，与没有内部构件的流化床相比，带有隔板浸入式垂直膜的流化床的等效气泡直径显着降低（高达 3.5 倍），这显示了改进的巨大潜力气泡到乳液相的传质速率。这项工作已被编辑选为本期的特色封面文章。这些实验结果还证明了管间隔件对流体动力学的非常重要的影响。此外，气泡相特性的分析证实，与没有内部构件的流化床相比，带有隔板浸入式垂直膜的流化床的等效气泡直径显着降低（高达 3.5 倍），这显示了改进的巨大潜力气泡到乳液相的传质速率。这项工作已被编辑选为本期的特色封面文章。5) 与没有内部构件的流化床相比，带有隔离件的浸入式垂直膜的流化床，显示了提高气泡到乳液相传质速率的巨大潜力。这项工作已被编辑选为本期的特色封面文章。5) 与没有内部构件的流化床相比，带有隔离件的浸入式垂直膜的流化床，显示了提高气泡到乳液相传质速率的巨大潜力。这项工作已被编辑选为本期的特色封面文章。