论文标题
带有分层结构的多孔介质中的调谐毛细管流
Tuning capillary flow in porous media with hierarchical structures
论文作者
论文摘要
多孔介质中的不混溶流体流体位移在许多工程应用中非常重要，例如增强石油回收，农业灌溉和地质二氧化碳存储。界面不稳定性引起的指法现象通常在位移过程中遇到，并且某种程度上有害，因为这种流体动力学不稳定性可以显着降低位移效率。在这项研究中，我们报告了孔几何形状的可能调整，旨在抑制具有分层结构的多孔介质中的毛细血管指法。通过孔隙尺度的模拟和理论分析，我们证明并量化了润湿性和分层几何形状对位移模式的组合效应，显示了从指法到紧凑模式的过渡。我们的结果表明，二阶多孔结构的孔隙率更高，位移可以在更广泛的润湿条件下保持紧凑。结合我们以前在这种媒体中的粘性指法的工作，我们可以在分层多孔介质中的流体流体流体控制控制中，从毛细管到粘性为主的模式的各种流量条件。这项工作的结论可以使微流体设备的设计受益，并调整多孔介质，以在现场尺度上提高流体位移效率。
Immiscible fluid-fluid displacement in porous media is of great importance in many engineering applications, such as enhanced oil recovery, agricultural irrigation, and geologic CO2 storage. Fingering phenomena, induced by the interface instability, are commonly encountered during displacement processes and somehow detrimental since such hydrodynamic instabilities can significantly reduce displacement efficiency. In this study, we report a possible adjustment in pore geometry which aims to suppress the capillary fingering in porous media with hierarchical structures. Through pore-scale simulations and theoretical analysis, we demonstrate and quantify combined effects of wettability and hierarchical geometry on displacement patterns, showing a transition from fingering to compact mode. Our results suggest that with a higher porosity of the 2nd-order porous structure, the displacement can keep compact across a wider range of wettability conditions. Combined with our previous work on viscous fingering in such media, we can provide a complete insight into the fluid-fluid displacement control in hierarchical porous media, across a wide range of flow conditions from capillary- to viscous-dominated modes. The conclusions of this work can benefit the design of microfluidic devices, as well as tailoring porous media for better fluid displacement efficiency at the field scale.
