Numerical simulation of fire in the parking lot of a commercial complex and the effect of ventilation on smoke concentration and visibility with Pyrosim software

One of the dangers that always threatens buildings is the risk of fire. Smoke is generated after a fire. In most cases, smoke generated by fire poses a far greater risk to human life than fire. Therefore, by controlling the smoke, the building and the people living in it can be protected and the damages caused by the fire can be reduced. In this study, smoke distribution in the parking lot of a complex was investigated using PyroSim software. Navier-Stokes equations for energy, mass survival were used to solve and large vortex simulation model was used for turbulence. Two scenarios were considered to investigate the fire. In the first scenario, parking without ventilation system was studied and in the second scenario, it was studied with ventilation system. Exhaust fan was used to evacuate the smoke and sapphire fan was used to supply fresh air. The results of these two simulations were compared with each other. The fire power was 4 MW. The results showed that in the first scenario, the smoke concentration is 0/003 mol / mol and the visibility is 2 meter. In the second scenario, the smoke concentration is 0/0002 mol / mol, which is 93% better than the first scenario. Also, the visibility was initially reduced to 2 meters and then increased to 20 meters in 600 seconds with the activation of the exhaust fan and smoke evacuation. In fact, visibility improved by 900% compared to the first scenario. Reducing the concentration of smoke and increasing visibility make it easier for people to evacuate during a fire, and people are able to live longer in a fire.