Smoking Room

Description

This project simulates cigarette smoke dispersion inside a smoking room using ANSYS Fluent, with an exhaust fan mounted on the upper wall and six air intakes at the base of the walls that draw in air due to the resulting negative room pressure. The room contains three occupants: a smoking woman seated on a bench near the domain's center, positioned relatively close to the exhaust fan's direction, a standing woman holding a cigarette in front of her, and a non-smoking man conversing with them nearby. The goal is to understand how air vortices shape smoke distribution in different parts of the room, which in turn informs where seating like a couch or bench should ideally be placed. The 3D geometry is built in Design Modeler and meshed in Fluent Meshing with a polyhedral grid of 965,187 elements.

Methodology

Cigarette smoke, treated as composed of four constituent materials, is modeled using both the Species Transport model and the Discrete Phase Model (DPM) together, capturing both the gas-phase dispersion and the discrete particulate behavior of the smoke. The exhaust fan on the ceiling is set to a negative pressure of -10 Pa to drive the room's ventilation, the energy equation is active to resolve temperature, and turbulence is handled with the standard k-epsilon model.

Analysis

The solution yields 2D and 3D contours of temperature, pressure, velocity, and smoke mass fraction, with 2D contours extracted on YZ and XZ planes through the room's center, along with time-resolved smoke pathlines. These pathlines show clearly how the combined intake and exhaust airflow shapes the smoke's movement through the room. The results indicate that seating placed closer to the exhaust fan's direction experiences a lower likelihood of air vortex formation, making that positioning preferable for reducing smoke exposure at seated locations. It's worth noting that smoke in this simulation originates only from the cigarette tips themselves; smoke inhaled and re-exhaled by occupants is not modeled, even though it could be a meaningful contributor to smoke distribution in real occupied spaces.