Darcy's law for multiphase flow

Darcy’s law for multiphase flow is a way to explain how different liquids and gases move through porous materials like soil or rocks.

Imagine you have a sponge (that’s the porous material). If you pour water onto the sponge, it will soak up the liquid and we call that water the “wetting phase”. If you pour oil onto the sponge, it won’t be absorbed as well because oil doesn’t mix well with water. Oil is the “non-wetting phase”. In multiphase flow, we need to consider how the wetting phase (water) and non-wetting phase (oil) interact with each other as they move through the porous material.

So, what does Darcy’s law say? It says that the rate at which the wetting phase moves through the porous material depends on how much pressure is being applied to it. The pressure is proportional to the flow rate of the wetting phase. This means that if we apply more pressure, the wetting phase will move faster through the porous material.

But what about the non-wetting phase? Well, it doesn’t move as easily through the porous material because it doesn’t want to mix with the wetting phase. Instead, it moves around the wetting phase, trying to find a way to get through the porous material.

Overall, Darcy’s law for multiphase flow helps us understand how different liquids and gases move through porous materials and the factors that affect their movement. It’s like trying to push water through a sponge with your hand – the harder you push, the faster the water will move through the sponge.