Porosity: Three-Phase Flow (Water, Air, and Kerosene) in a Porous Channel

Three-Phase Flow Simulation in a Zigzag Channel Using ANSYS Fluent

Introduction

This project simulates a three-phase flow mixture consisting of air, water, and kerosene within a square cross-section channel using ANSYS Fluent. The channel geometry includes a vertical section with two inlet openings at its top and bottom, connected to a zigzag horizontal section terminating in an outlet. In the initial state, only air occupies the channel; as the simulation proceeds, water enters through the upper inlet while kerosene enters through the lower inlet, allowing the three-phase interaction to develop over time.

Geometry and Mesh

The three-dimensional geometry was designed in Design Modeler, consisting of a vertical channel for fluid entry connected to a zigzag horizontal path formed by a series of perpendicular teeth-like segments. The channel cross-section is square with a side length of 0.0002 m, featuring two inlet sections at the top and bottom of the vertical portion and a single outlet at the end of the horizontal zigzag section. The domain was meshed using ANSYS Meshing with a structured mesh totaling 416,000 elements.

Methodology

The VOF multiphase model was used to capture the interaction between the three fluid phases. A porous zone with a porosity coefficient of 0.1 was defined within the channel to represent the flow resistance encountered along the path. Both inlet sections were assigned pressure-inlet boundary conditions with a relative pressure of 1000 Pa, while the single outlet was defined as a pressure outlet with a relative pressure of 0 Pa. The simulation was solved using a transient solver to track the volume fraction evolution of each phase over time, running for a total of 5 seconds with a time step of 0.1 seconds.

Results and Conclusion

Two- and three-dimensional contours of pressure, velocity, and volume fraction for each of the water, air, and kerosene phases were obtained at the final second of the simulation. These results capture the progressive redistribution of the three phases as water and kerosene advance through the vertical and zigzag sections of the channel, illustrating how the porous zone and channel geometry jointly influence the multiphase flow development and phase distribution throughout the domain.