Modern architecture relies on smart designs to keep buildings cool and clean. One of the best designs is the Ventilated Brick Wall. This structure leaves a narrow air gap between the outer brick exterior and the inner room wall. According to research by Buratti et al. [1], this gap uses natural airflow to block summer heat. Additionally, Zhou et al. [2] showed that this airflow can also act like a vacuum, removing harmful dust particles from the room.

This report is a comprehensive Ventilated Wall fluent simulation tutorial. We will use a 3D computer model to show exactly how a ventilated wall manages both heat and indoor air quality. By mastering this CFD Analysis of Ventilated Brick Wall, engineers can design healthier homes. For more foundational lessons on modeling indoor air quality and thermal comfort, please explore our HVAC tutorials.

• Reference [1]: Buratti, Cinzia, et al. “Development and optimization of a new ventilated brick wall: CFD analysis and experimental validation.” Energy and Buildings168 (2018): 284-297.
• Reference [2]: Zhou, Yu, et al. “The effects of ventilation and floor heating systems on the dispersion and deposition of fine particles in an enclosed environment.” Building and Environment125 (2017): 192-205.

Figure 1: A prototype of the constructed ventilated brick wall in a laboratory setting [1].

Simulation Process: DPM, DO Radiation, and Solar Load Fluent Setup

To understand how dust moves, we performed a Ventilated Wall ANSYS Fluent simulation using a multiphase approach. We modeled the room air as a continuous fluid, but we tracked the tiny dust particles individually. This method is called the Eulerian-Lagrangian approach, utilizing the Discrete Phase Model (DPM) in Fluent.

We activated two highly important physics models for this Ventilated Wall fluent setup:

1. DO radiation fluent model & Solar Load: We turned on the Discrete Ordinates (DO) model to simulate the sun’s rays physically hitting the outside of the brick wall.
2. Two-way DPM coupling: This crucial setting ensures that the flowing air pushes the dust particles, and the mass of the dust particles also slightly pushes back on the air, making the fluent simulation highly realistic.

Post-processing: How Solar Heat Creates a Natural Air Purifier

To truly understand this Ventilated Wall CFD simulation, we must look strictly at the cause-and-effect data provided by the simulation’s physics. The Cause (Solar Buoyancy): The entire system is powered by the sun. The Solar load fluent setup calculates the sunlight hitting the outer brick wall. As the brick gets hot, it transfers heat directly into the air trapped inside the narrow wall cavity. When this pocket of air gets warm, its density drops. It becomes light. This creates a powerful upward force called buoyancy. This buoyancy is the invisible engine of the simulation; it turns the wall cavity into a natural chimney, pulling air continuously upward.

The Effect (Particle Suction and Removal): Because the hot air is rushing up and out of the top of the wall cavity, it creates a vacuum (suction) at the bottom vents near the floor. Look at the data in Figure 3 (Particle Velocity). This image is the definitive proof of the wall’s cleaning power. You can see the dust particles being sucked directly from the floor level into the wall. As they enter the narrow ventilation channel, they accelerate, indicated by the high-speed yellow and green color regions, sweeping the dust rapidly up and out of the building.

Figure 2: Particle residence time, showing how the Ventilated Wall CFD system removes particles near it (yellow/green) while uncaptured particles remain for longer (red).

We can verify this cleaning effect by looking at Figure 2 (Particle Residence Time). “Residence time” means how long a dust particle stays inside the room before being removed.

• The Red Tracks: Dust particles that are far away from the wall are not caught by the suction. They slowly settle to the floor and stay in the room for a very long time, which is why their tracks are red.
• The Yellow/Green Tracks: Dust particles located near the ventilated wall are quickly grabbed by the upward draft. They have a very short residence time (yellow/green), proving they are rapidly removed from the living space.

This CFD Analysis of Ventilated Brick Wall clearly proves that we can harness solar energy (the DO radiation cause) to create a powerful, natural ventilation engine (the chimney effect) that acts as a continuous air purifier, sucking dust right off the floor.

Figure 3: Velocity of discrete dust particles, showing them being accelerated up and into the ventilation cavity.

Key Takeaways & FAQ

• Q: What is the DO radiation fluent model used for here?
  • A: It simulates the real-world Solar load. It calculates how sunlight heats the exterior brick, which in turn heats the air in the cavity to create the upward buoyancy draft.
• Q: What does the Discrete Phase Model (DPM) do?
  • A: In this Ventilated Wall CFD simulation, DPM tracks individual dust particles to see exactly where they travel, how fast they move, and how long they stay in the room.
• Q: Why do particles near the wall have yellow/green residence times?
  • A: Yellow/green indicates a short time spent in the room. The upward chimney effect created by the heated wall creates suction at the floor, quickly removing these nearby particles.