Direct pore-scale modeling of two-phase flow: Investigation of the effect of interfacial tension and contact angle

The process of fluid flow displacement in porous media has recently gained great prominence owing to its widespread usage in a variety of industries, especially in the case of pore scale investigations. Although, many studies have been conducted to address pore-scale investigations in both modeling and experimental approaches, the role of interfacial tension and contact angle on pore-scale phenomena is less focused. In this work, direct pore-scale modeling was used to precisely examine the effect of interfacial tension and contact angle on the fluid flow at the microscale. Also, several pore-scale mechanisms, including Haines jump and dynamic breakup mechanisms, were observed. Therefore, the volume of fluid method, as an astonishing free-surface modeling method, was utilized in an open-source finite-volume computational fluid dynamics software package (OpenFOAM). To validate the simulation results, we designed and performed a set of corresponding micromodel experiments. The investigation of the effect of interfacial tension illustrated that when interfacial tension is decreased, a thin film of the wetting fluid propagates along the solid surface. At high interfacial tension (capillary numbers less than 6 × 10−4) cooperative pore filling was observed, while at low interfacial tension large deformations were obvious. Also, when the contact angle was less than 90◦, cooperative pore filling was the main mechanism, while at contact angles greater than 90◦ individual pore invasion was the active mechanism. © 2021 by Begell House, Inc. www.begellhouse.com