Including specific interfacial area and saturation of the percolating phase into two-phase porous media flow models, on the Darcy scale, enhances our ability to capture the physical properties of porous media flow more effectively. Using optical microscopy and microfluidic devices, we perform sequential drainage and imbibition experiments. The relevant processes, images, and boundary pressures are monitored, recorded, and logged at all times. For comparative purposes, two PDMS micromodels are used, one with an ortho-canonical, homogeneous, and the other with a periodic heterogeneous pore network, with similar macro- but different pore-scale properties. After processing the images, parameters like interfacial area belonging to percolating and non-percolating phases and the corresponding phase saturations are determined. Our experimental results show that the relation between specific interfacial area and saturation of the percolating invading phase is a linear relationship with interesting properties. Additionally, after a number of fluid displacement processes (drainage and imbibition), and for both pore networks, unique flow paths for both phases are formed. We speculate that this happens due to the establishment of an effective porous medium, meaning a hydro-dynamically active region within the pore space where the corresponding phase remains connected and flowing, where the capillary forces act as the guide for creating the “path of least resistance” in a highly viscous flow regime by keeping the non-percolating phases in place. As the results can be specific to our experiments, more work needs to be done toward the potential generalization of these findings, especially in 3D flow domains.

中文翻译：

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在多孔介质中形成常见的优先两相位移路径


在达西尺度上，将渗透相的特定界面面积和饱和度纳入两相多孔介质流模型中，可以增强我们更有效地捕获多孔介质流物理特性的能力。使用光学显微镜和微流体设备，我们进行顺序引流和吸吸实验。相关过程、图像和边界压力始终受到监控、记录和记录。为了进行比较，使用了两个 PDMS 微模型，一个具有正交规范、均匀，另一个具有周期性异质孔隙网络，具有相似的宏观但不同的孔隙尺度特性。处理图像后，确定属于渗流相和非渗流相的界面面积等参数以及相应的相饱和度。我们的实验结果表明，比界面面积与渗流侵入相饱和度之间的关系是具有有趣性质的线性关系。此外，经过许多流体置换过程（排水和渗吸），对于两个孔隙网络，两个相都形成了独特的流路。我们推测，这是由于建立了有效的多孔介质，这意味着孔隙空间内的流体动力学活动区域，相应的相保持连接和流动，其中毛细管力作为指导，通过保持非渗流相在位，在高粘性流态中创建“阻力最小路径”。由于结果可能特定于我们的实验，因此需要做更多的工作来概括这些发现的潜在泛化，尤其是在 3D 流域中。