Making fuel cleaner by taking out harmful sulfur is a very big job today. This process, called Liquid Fuel Desulfurization CFD, helps us get cleaner energy and protects our planet. How the liquids move inside the cleaning machines, called “hydrodynamics,” is super important for how well we can remove these bad chemicals. In these machines, the way fluids mix and form tiny drops directly decides if the sulfur removal works or not. This is because the mixing controls how fast sulfur moves from the fuel into the cleaning liquid. When engineers design these systems, they must carefully balance things like how liquids stick together (surface tension) and how drops form. New computer tools, like Computational Fluid Dynamics (CFD), help us see these hidden movements. Our study uses CFD to look closely at how fuel and cleaning liquids interact in a tiny T-shaped channel (Figure 2), following a guide from a research paper [1]. This helps us find new ways to clean fuel better and save energy in oil refineries.

• Reference [1]: Al-Azzawi, Marwah, et al. “Hydrodynamic investigation on deep desulfurization of liquid fuel at the microscale.” Chemical Engineering & Technology10 (2020): 1951-1958.

Figure 1: Experimental and numerical flow patterns for Liquid Fuel Desulfurization CFD, adapted from reference [1].

Simulation Process: Building a Microscale Desulfurization Model in Fluent

To study Liquid Fuel Desulfurization Fluent, we first drew a very small T-shaped channel, like the one shown in Figure 2. This channel is tiny, with all its parts having a diameter of only 1 millimeter. The inlet channel was 8 millimeters long, and the main channel was 30 millimeters long. We used a program called Design Modeler to draw this shape. Then, we used another program called ICEM to create a very detailed map of tiny boxes, called a structured grid, with 380,296 cells. This careful grid helps our computer get very accurate results. Since we have two different liquids (fuel and a cleaning material called PEG) flowing together, we used a special setting in ANSYS Fluent called the Volume Of Fluid (VOF) multiphase model. This model helps us see how the two liquids stay separate and how they interact. Because how liquids stick to surfaces is important, we also looked at “wall adhesion” and “contact angle” effects, just like the reference paper [1]. This setup allowed us to simulate the Sulfur Removal CFD process in detail.

Figure 2: Schematic of the T-junction channel geometry used for the Sulfur Removal Fluent simulation.

Post-processing: CFD Analysis of Droplet Dynamics for Enhanced Sulfur Removal

The simulation results provide a clear story of cause and effect, vividly showing the complex process of fuel droplet formation and its importance for effective sulfur removal Fluent. Figure 3, the Fuel Volume Fraction contour, immediately reveals the main cause: the precise geometry of the T-junction and the careful balance of surface tension forces. The direct effect is the consistent and perfect formation of fuel droplets (shown in red-orange) as the fuel stream enters the main channel, moving through the blue cleaning solvent. These images show a stable “slug flow” pattern, where droplets are evenly spaced and keep their shape, just like little cleaning units. This uniform formation is crucial because it creates the largest possible surface area for sulfur to transfer from the fuel into the cleaning liquid. The most important achievement of this Liquid Fuel Desulfurization CFD analysis is its precise capture of these stable, consistent droplet formation dynamics, which directly confirms the VOF model’s accuracy in predicting interfacial phenomena critical for maximizing sulfur transfer efficiency in microscale desulfurization processes. Furthermore, as seen in Figure 4 (3D view), the green areas at the edges of the droplets clearly show the “phase interface,” which is exactly where the sulfur molecules move from the fuel into the cleaning solvent. The smooth color change from red (pure fuel) to blue (pure solvent) through these green zones proves that the simulation accurately shows the concentration changes that drive the cleaning process. This detailed view of droplet integrity and the active mass transfer zones provides engineers with vital information to optimize T-junction designs, ensuring better mixing and ultimately, much cleaner fuel with less energy.

Figure 3: Contour of Fuel Volume Fraction from the Liquid Fuel Desulfurization Fluent analysis, showing consistent droplet formation.

Figure 4: 3D perspective view of Fuel Volume Fraction displaying the stable slug flow pattern during Sulfur Removal CFD.