In laboratories and industrial factories, protecting workers from dangerous toxic gases like ammonia is the number one priority. Sometimes, you cannot build physical walls because workers need space to move. Instead, engineers use an “Air Curtain.” This is an invisible wall made entirely of fast-moving air. To design this safely, engineers perform an Air Curtain Ventilation CFD simulation. By building a virtual room, we can see exactly how the invisible air stops the toxic gas from spreading.

This report is a complete Air Curtain Ventilation fluent simulation tutorial. We will use ANSYS Fluent to visualize how to trap and extract hazardous gas. By mastering this CFD Analysis of Ammonia Removal, you can design safer workspaces. For more lessons on modeling indoor air quality and ventilation, please visit our HVAC tutorials.

Figure 1: An air curtain ventilation system installed in a laboratory for contaminant control.

Simulation Process: Species Transport Fluent Model Setup

To understand how two different gases mix, we set up an Air Curtain Ventilation ANSYS Fluent project. We built a 3D model of a workspace. In this virtual room, dangerous ammonia gas is leaking from the floor. At the same time, the air curtain system is located on the ceiling, blowing completely clean air downwards.

The most important step in this Air Curtain Ventilation fluent setup is activating the Species Transport fluent model. Standard CFD only calculates moving air. The Species Transport model allows ANSYS Fluent to track multiple different chemicals at the same time. It mathematically calculates the exact percentage (mass fraction) of ammonia floating in the clean air. We ran this simulation until the airflow reached a steady, balanced state.

Post-processing: Analytical Cause and Effect of Air Momentum

To truly understand this Ammonia Removal simulation, we must strictly analyze the visual data and understand the physics of “Cause and Effect.” The Cause (High-Speed Momentum): The engine of this entire safety system is located at the ceiling. The system injects clean air straight down into the room. Look at the Velocity Streamlines (Figure 3). The software calculated that these air jets reach speeds of 4.4 m/s. This is a very high velocity. In fluid dynamics, high velocity creates “momentum”—a heavy physical force. This 4.4 m/s downward momentum is the direct cause of everything that happens next.

When this fast, heavy air shoots down, it creates a physical barrier that the ammonia simply cannot push through. We can prove this by looking at the Ammonia Mass Fraction contour (Figure 2). This image shows the exact concentration of the toxic gas. Notice the incredibly sharp boundary. Inside the curtain zone, the colors are red and yellow, meaning the ammonia is highly concentrated and trapped. Just inches outside the curtain, the color instantly turns to dark blue, meaning the air is perfectly clean and safe. The 4.4 m/s momentum successfully built an invisible brick wall.

Figure 2: Ammonia mass fraction contour from the fluent simulation, proving the containment effect where red/yellow (toxic) gas is sharply separated from blue (clean) air.

Trapping the gas is only half the job; we must remove it. Look again at the Velocity Streamlines (Figure 3). The air curtain jets are blowing down from multiple sides. When these fast jets hit the floor and crash into each other in the center of the room, they have nowhere to go but up. This collision forces the air to violently change direction, creating a massive, focused updraft right in the middle of the trapped ammonia zone. This updraft acts exactly like a chimney, grabbing the red/yellow ammonia and shooting it straight up into the ceiling exhaust vents.

This highly accurate CFD Analysis of Ammonia Removal proves that simply blowing air is not enough. You must use high-velocity momentum (4.4 m/s) to simultaneously trap the gas (containment) and force it upwards (removal).

Figure 3: Velocity streamlines showing the 4.4 m/s downward jets colliding and creating a focused upward chimney to exhaust the ammonia.

Key Takeaways & FAQ

• Q: What does the Species Transport fluent model do?
  • A: It allows ANSYS Fluent to calculate and track the mixing of different chemicals—in this case, mapping exactly where the ammonia gas is located in the clean air.
• Q: How does the air curtain contain the ammonia?
  • A: The high velocity (4.4 m/s) of the clean air jets creates heavy momentum. As seen in the mass fraction contour, this momentum acts as an invisible barrier that the ammonia cannot penetrate.
• Q: How is the toxic gas actually removed?
  • A: When the downward jets hit the floor and collide in the center, they create a strong, focused updraft (a chimney effect) that carries the contained ammonia straight up to the exhaust vents.