A Two-phase Bubbly Flow Fluent simulation is a computer model used to study what happens when gas bubbles move through a liquid. This type of Multiphase Flow Simulation is very important for many industries, like chemical engineering and wastewater treatment. A Rising Bubble Simulation helps us understand the forces that act on a bubble. The bubble rises because it is less dense than the liquid, but its shape and speed are changed by the liquid’s properties. Understanding Bubble Dynamics Fluent helps engineers design better equipment for mixing and chemical reactions. This study uses the methods from the key reference paper by Ansari et al. [1] to ensure our model is accurate.

• Reference [1]: Ansari, M. R., A. Hadidi, and M. E. Nimvari. “Effect of a uniform magnetic field on dielectric two-phase bubbly flows using the level set method.” Journal of Magnetism and Magnetic Materials23 (2012): 4094-4101.

Figure 1: A schematic of the vertical channel geometry used for the Bubbly Flow CFD simulation, based on the reference paper [1].

Simulation Process: Fluent Setup, Coupled Level Set-VOF for Sharp Interface Tracking

To perform this Two-phase Bubbly Flow CFD study, we created a 2D geometry of a vertical rectangular channel. Inside this channel, we placed a single gas bubble within a continuous liquid. The simulation was started from a stationary condition, meaning nothing was moving at time zero. The initial bubble was defined as having a perfect spherical shape. We then created a high-quality structured grid using 25,520 cells to accurately solve the fluid flow. The most important feature of this simulation in ANSYS Fluent was the use of the Coupled Level Set + Volume Of Fluid (VOF) multiphase model. The VOF model is good for tracking the general location of the bubble, but for flows like this where surface tension is important, the Level Set method is needed. Using the Level Set method gives a much better calculation of the interface curvature, which is critical for getting the bubble shape right and reducing incorrect currents in the simulation.

Post-processing: CFD Analysis, Bubble Deformation and Wake Region Dynamics

The contour from the simulation provides a clear visual of the complex physics at play. From an engineering standpoint, the most striking result is the bubble’s final shape. It is not a sphere, but has deformed into a crescent shape (like a flattened cap). This shows a strong interaction between the upward buoyancy force, which pushes the bubble up, and the drag forces from the liquid, which resist its movement and change its shape. The thin, sharp line between the red bubble and blue liquid confirms that our model is correctly capturing the interface. The concave, or indented, shape at the bottom of the bubble is very important. This indicates the formation of a wake region, an area of swirling, low-pressure fluid that is created as the liquid flows around the rising bubble.

Figure 2: A contour from the Fluid Dynamics Simulation showing the bubble’s shape and position after rising, demonstrating the results of the Coupled Level Set-VOF model.

This analysis has direct and important meaning for industrial processes. In equipment like bubble column reactors, the amount of surface area between the gas and liquid controls how fast reactions happen. The deformed, crescent shape has a larger interfacial area than a perfect sphere of the same volume. This means that mass transfer rates can be higher than what a simpler model would predict. The presence of the wake also increases mixing in the liquid. The most important achievement of this simulation is its ability to accurately predict the complex deformation of the bubble, proving that simple models assuming spherical bubbles are wrong for these conditions and providing a more accurate tool for designing and optimizing industrial reactors.