Designing Jet Fan Ventilation for an Underground Car Park by CFD Simulations

Abstract

The aim of this study was to design a fire ventilation system with impulse jet fans for an underground car park. With respect to the number of parameters affecting the spread of smoke that need to be considered, there is a good chance of miscalculations if only conventional plain calculations are used in the design process. To avoid mistakes, visualize the fluid flow, and to compare the design variants it is practical to use computational fluid dynamics (CFD). In this study, CFD simulations were used to compare alternative designs of a fire ventilation system. In one alternative the exhaust shafts were located in both parts of the car park and the jet fans were directed to the corresponding shafts. The air exchange rate was 10-times per hour. In another alternative both exhaust shafts were located on one side opposite to the main air supply, and the air exchange rate was 15-times per hour. The results showed preference of the second alternative, when the smoke was completely exhausted and the visibility improved substantially, whereas in the first alternative the car park was not sufficiently ventilated even 600 seconds after the fire had been put out. The results emphasize that proper location of elements of the ventilation system is crucial to attain high efficiency of fire ventilation.