Abstract:
The covered car parks need to have means of ventilation, natural or
mechanical, that provide the exhaust of the combustion products released by the
engines of the vehicles passing through and to control the smoke released by fire. In last
years, a new mechanical ventilation system appeared, based on the use of axial
ventilators (jet fans) suspended under the car park ceiling. Jet fans generate the
momentum necessary to promote the internal ventilation flow. In this way, the inlets and
outlets may be concentrated in some points of the underground car park. Due to the
general geometry of car parking, the flow can be rather complex, so parameters like the
jet fans position, orientation and velocities have to be carefully chosen [1; 2]. While
widely accepted design recommendations for this kind of projects are missing, the use
of CFD software, as complement and auxiliary tool in the evaluation of ventilation
design, can be of great interest. In this context, CFD simulations were carried out,
using a freeware code (the FDS - Fire Dynamics Simulator), to evaluate and confirm
the performance of an existing ventilation system, installed in an underground car park,
in a fire scenario. The CFD results were compared with experimental values.