A Permeating Liquid Droplet CFD simulation is essential for improving water filtration systems. In many industries, like oil recovery, we need to separate small drops of oil from water using special filters called membranes. Understanding how a permeating liquid droplet squeezes through tiny holes is very difficult to see in real life. Therefore, engineers use Permeating Liquid Droplet ANSYS Fluent simulations to model this process on a computer.

By using moving Oil droplet CFD simulation, we can predict if the oil will pass through the filter or get stuck. This simulation focuses on the competition between different forces, like drag from the water and surface tension of the oil. This report details a Permeating oil droplet Fluent study based on the scientific work of Salama (2020). We use advanced VOF modeling to track the exact shape of the droplet as it deforms. This helps engineers design better membranes that stay clean and work efficiently. For more examples of mixing and separating fluids, please explore our Multiphase tutorials: https://cfdland.com/product-category/module/multiphase-cfd-simulation/

• Reference [1]: Salama, Amgad. “Investigation of the onset of the breakup of a permeating oil droplet at a membrane surface in crossflow filtration: A new model and CFD verification.” International Journal of Multiphase Flow126 (2020): 103255.

Figure 1:  A schematic diagram showing the theoretical pinning mechanism of an oil droplet over a pore opening [1].

Simulation Process: Fluent VOF Setup and Mesh Adaptation for Droplet Physics

The simulation process for this Permeating Liquid Droplet CFD analysis started with a specific 3D geometry. We followed the validated research to create a channel with a single pore opening at the bottom and surrounding walls with Periodic boundary condition. To solve the equations accurately, we generated a mesh using polyhedral cells. The final mesh contained 63,908 cells. Polyhedral cells are excellent for ANSYS Fluent because they give accurate results with fewer cells than other types.

Inside the software, we used the VOF modeling (Volume of Fluid) method. This is the best tool for tracking the interface between the oil droplet and the surrounding water. Because the droplet moves and changes shape, we used a “transient” (time-dependent) solver. A key part of the Permeating oil droplet Fluent setup was the Mesh Adaptation technique. This feature automatically made the cells smaller and denser right around the droplet skin. This allows the simulation to capture tiny changes in shape without wasting computer power on empty spaces. We also applied periodic boundary conditions to mimic a continuous industrial filtration process.

Figure 2: The computational domain geometry representing the crossflow channel and the membrane pore [1].

Post-processing: Droplet Pinning and Interface Deformation Analysis

The post-processing analysis provides a deep look into the physics of filtration. We must examine the Volume of Fraction contours in Figure 3 to understand the results. The red shape represents the moving Oil droplet. The Permeating Liquid Droplet ANSYS Fluent results show that the droplet does not simply flow past the hole. Instead, it gets “anchored” or pinned at the pore opening. The contours clearly show the droplet tilting forward due to the crossflow drag, while a “leg” of oil starts to penetrate down into the vertical channel.

This visual evidence confirms a critical physical phenomenon. The simulation captures the exact moment where hydrodynamic forces compete with capillary forces. The pressure pushes the oil down, but the surface tension tries to hold it together. In the bottom frames of Figure 3, we can see the droplet forming a distinct “neck” structure. This proves that the Permeating Liquid Droplet CFD model is accurate.

Figure 3: Volume of Fraction (VOF) contours from ANSYS Fluent, showing the red oil droplet deforming and anchoring at the pore opening over time.

Figure 4: Mesh contours displaying the 63,908 polyhedral cells with dynamic Mesh Adaption clearly refining the grid around the droplet interface.

Furthermore, the Mesh contour in Figure 4 demonstrates why this result is reliable. The image shows a dense layer of tiny cells perfectly hugging the droplet. This is the Dynamic Mesh Adaption working correctly. For a membrane designer, this is vital information. It proves that under these specific flow conditions, the oil will clog the pore rather than passing through easily. By seeing this deformation and breakup behavior, a manufacturer can adjust the flow rate or the pore size to prevent fouling and make the filter last longer. The simulation acts as a “virtual microscope,” allowing engineers to optimize the separation process without expensive lab tests.