Fire safety is a critical characteristic of any populated space, mainly those with high risks such as difficult exit paths or with flammable materials. It must be ensured by Architects and engineers that place should be safe under both normal and emergency conditions for its occupants. The purpose of the CFD simulation is to predict ventilation system effectiveness and make our ventilation system more efficient by improving the performance of smoke management system. When there is fire taken place in car parking area or in a building it is necessary to remove smoke from the parking area quickly and maintaining the temperature of that area. It is also important to maintain the visibility of the area to certain extent that a person can move to a safe place easily. In case of fire environment, FDS (Fire Dynamics Simulator), a CFD tool is especially used to implement the computer simulation for fire driven fluid flow (smoke and heat transport). Fire Dynamics Simulator is optimized to obtain a more efficient, specialized workflow for the analysis of fires.
THE CONDITIONS FOR SIMULATION
Forced air inlet and outlets
After a time delay all jet fans start to operate.
Total number of jet fans
Fresh air inlet temperature
Fire burning material
These simulation results represent the smoke propagation pattern to assess the smoke management of the ventilation system. The examination of time evolution of concentration is done to detect danger zones. Plots for smoke propagation after five minutes and ten minutes are presented in figure 1 & 2
Figure 1: smoke concentration five minutes after the fire starts
Figure 2: smoke concentration ten minutes after the fire starts
The temperature distribution is calculated which is showing that high levels are confined to the fire source area and that exit zones keep low levels, as shown in the given figure.
Figure 3: Temperature distribution ten minutes after the fire starts
The sight visibility is an important factor in case of fire. Another simulation is the sight visibility at every point. In the following plot, red areas have high(clear) visibility and blue areas have low(bad) visibility.
Figure 4: visibility at a height of 1.7 meters, ten minutes after the fire starts
This diagram represents the airflow velocity plot. It shows the action of the jet fans and the general ventilation pattern.
Figure 5: Airflow velocity magnitude at jet fans location height
The code compliances can be easily checked by CFD simulation tools. Also, we can easily identify design improvement and optimize testing for performance evaluation.