Pollution of the Street between Buildings CFD Simulation

Description

Pollution of the Street between Buildings CFD Simulation, ANSYS Fluent Tutorial

Description

Motor vehicles are a significant source of air pollution. The raised health risks associated with living close to roads are unlikely to be explained by PM_2.5 mass since this is only slightly elevated near roads. In contrast, levels of such pollutants as ultrafine particles, carbon monoxide, NO₂, black carbon, polycyclic aromatic hydrocarbons, and some metals are more elevated near roads.

Motor vehicles produce large quantities of carbon dioxide, carbon monoxide, hydrocarbons, nitrogen oxides, PM, and substances known as mobile source air toxics, such as benzene, formaldehyde, acetaldehyde, 1,3-butadiene, and lead.

This project uses a 3D simulation of buildings where a street is placed between them.

The geometry of the solution is a 3D rectangular domain whose length in X, Y and the Z direction is 40m and 20m, and 25m, respectively.

There are two buildings; the first is by the length of 3m, 3m, and 15m in positive X, Y, and Z directions. The second is 3m, 10m, and 15 in the same direction. Design Modeler software is used to create the geometry of the solution. ANSYS Meshing software is used to generate 274,496 structured elements.

This CFD project is the 12th episode of the ANSYS Fluent General Training Course.

Methodology: Pollution of the Street between Buildings

The simulation is steady, and the Pressure-based solver type is used due to the incompressibility of the working fluid. The gravitational acceleration effects are considered by defining 9.81 m/s^2 in the negative direction of Y. The Species Transport model is used to solve and model the pollution rising from the street.

Conclusion

At the end of the solution process, two-dimensional contours of pressure, velocity, and volume fractions of pollution and air are obtained. Also, the contours are visible every five iterations.

The static pressure at the left side of the buildings is high, while velocity rises after hitting the top of them. Also, the volume fraction of the pollution tends to the left building side because of the airflow movement between buildings.

The average of static pressure amount at the inlet is plotted as follows as a criterion to assure the convergence of the solution: