DTRM Model: Atrium Natural Ventilation

DTRM Radiation Model, Atrium Natural Ventilation

Description

This project simulates natural ventilation within a three-story atrium building using the Discrete Transfer Radiation Model (DTRM) in ANSYS Fluent, incorporating the combined effects of solar radiation and internal heat sources on airflow and temperature distribution throughout the space.

The 3D geometry represents a three-story atrium building with rooms flanking both sides, featuring multiple air inlets, outlets, and a central atrium void connecting all levels. The domain was meshed using an unstructured grid totaling 709,511 cells.

Methodology

Radiation heat transfer was captured using DTRM, which approximates radiative transport using a discrete set of rays traced through the domain. Solar ray tracing was incorporated to accurately capture solar radiation effects, accounting for both direct and diffuse irradiation based on the building's specific geographical location and time — modeled for Montreal, Canada, at 13:00 on July 15th. Natural convection modeling captured the resulting buoyancy-driven air movement throughout the atrium and connected rooms.

Boundary conditions were configured for the various air inlets, outlets, and internal heat sources, with material properties assigned to the glass exterior and internal structural elements to appropriately capture their radiative and thermal behavior.

Conclusion

Results include temperature distributions throughout the atrium and surrounding rooms, pressure and velocity fields illustrating airflow movement patterns, density variations driving the natural ventilation process, and velocity vectors showing the resulting airflow circulation throughout the building.

Together, these results demonstrate how solar radiation entering through the glass exterior interacts with internal heat sources to drive buoyancy-induced natural ventilation throughout the atrium — offering insight directly applicable to optimizing naturally ventilated building designs, atrium planning, and solar gain management for improved thermal comfort and energy efficiency in multi-story architectural spaces.