Pore-scale effects during the transition from capillary- to viscosity-dominated flow dynamics within microfluidic porous-like domains.

We perform a numerical and experimental study of immiscible two-phase flows within predominantly 2D transparent PDMS microfluidic domains with disordered pillar-like obstacles, that effectively serve as artificial porous structures. Using a high sensitivity pressure sensor at the flow inlet, we capture experimentally the pressure dynamics under fixed flow rate conditions as the fluid-fluid interface advances within the porous domain, while also monitoring the corresponding phase distribution patterns using optical microscopy. Our experimental study covers 4 orders of magnitude with respect to the injection flow rate and highlights the characteristics of immiscible displacement processes during the transition from the capillarity-controlled interface displacement regime at lower flow rates, where the pores are invaded sequentially in the form of Haines jumps, to the viscosity-dominated regime, where multiple pores are invaded simultaneously.

Effect of Nanoscale Surface Textures on Multiphase Flow Dynamics in Capillaries.

Multiphase flow through porous media is important in a wide range of environmental applications such as enhanced oil recovery and geologic storage of CO. Recent in situ observations of the three-phase contact line between immiscible fluid phases and solid surfaces suggest that existing models may not fully capture the effects of nanoscale surface textures, impacting flow prediction. To better characterize the role of surface roughness in these systems, spontaneous and forced imbibition experiments were carried out using glass capillaries with modified surface roughness or wettability.

Velocity distributions in trapped and mobilized non-wetting phase ganglia in porous media.

Understanding the mobilisation of trapped globules of non-wetting phase during two-phase flow has been the aim of numerous studies. However, the driving forces for the mobilisation of the trapped phases are still not well understood. Also, there is little information about what happens within a globule before, at the onset and during mobilization.

Manufacturing a Micro-model with Integrated Fibre Optic Pressure Sensors.

The measurement of fluid pressure inside pores is a major challenge in experimental studies of two-phase flow in porous media. In this paper, we describe the manufacturing procedure of a micro-model with integrated fibre optic pressure sensors. They have a circular measurement window with a diameter of 260  , which enables the measurement of pressure at the pore scale.