Subburaj Rahul, Tang Yali, Deen Niels G
Power and Flow Group, Department of Mechanical engineering, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.
Eindhoven Institute for Renewable Energy Systems, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands.
Ind Eng Chem Res. 2023 May 8;62(45):19302-19310. doi: 10.1021/acs.iecr.3c00265. eCollection 2023 Nov 15.
In the concept of a microstructured bubble column reactor, microstructuring of the catalyst carrier is realized by introducing a static mesh of thin wires coated with catalyst inside the column. Meanwhile, the wires also serve the purpose of cutting the bubbles, which in turn results in high interfacial area and enhanced interface hydrodynamics. However, there are no models that can predict the fate of bubbles (cut/stuck) passing through these wires, thus making the reactor optimization difficult. In this work, based on several typical bubble-wire interacting configurations, we analyze the outcomes by applying the energy balance of the bubble focusing on buoyancy and surface tension. Two limiting cases of viscosity, corresponding to the ability of the bubble to reconfigure into the lowest energy state, are investigated. Upon analysis, it is observed that a narrow mesh spacing and a smaller bubble Eötvös number generally result in bubbles getting stuck underneath the wire. We have obtained the threshold grid spacing and the critical Eötvös number for bubble passage and bubble cutting, which are verified by the direct numerical simulation results of bubble passing through a single mesh opening. The derived energy balance is generalized to large meshes with multiple openings and different configurations. Finally, a closure model based on the outcomes of energy-balance analysis is proposed for Euler-Lagrange simulations of microstructured bubble columns.
在微结构鼓泡塔反应器的概念中，通过在塔内引入涂覆有催化剂的细金属丝静态网格来实现催化剂载体的微结构化。同时，这些金属丝还起到切割气泡的作用，进而导致高界面面积并增强界面流体动力学。然而，目前尚无模型能够预测气泡穿过这些金属丝时的命运（被切割/卡住），从而使得反应器的优化变得困难。在这项工作中，基于几种典型的气泡 - 金属丝相互作用构型，我们通过应用关注浮力和表面张力的气泡能量平衡来分析结果。研究了对应于气泡重新配置成最低能量状态能力的两种极限粘度情况。经分析发现，较窄的网格间距和较小的气泡欧托沃斯数通常会导致气泡卡在金属丝下方。我们获得了气泡通过和气泡切割的阈值网格间距和临界欧托沃斯数，这些结果通过气泡穿过单个网格开口的直接数值模拟结果得到了验证。所推导的能量平衡被推广到具有多个开口和不同构型的大网格。最后，基于能量平衡分析的结果，为微结构鼓泡塔的欧拉 - 拉格朗日模拟提出了一个封闭模型。
