Experimental and numerical investigation of semi-transverse ventilation system during the fire test

The focus of this full-scale study is to investigate the operation of the Bosrucktunnel ventilation during the fire. In this regard, the performance of the ventilation system and all related sub-systems were evaluated in a standard Commissioning test. For this purpose, a fire test with a heat release rate of 3-5 MW was considered according to RVS standard. The mentioned capacity of the fire is equivalent to a common passenger car fire. This fire capacity can’t represent a clear perspective from the ventilation operation during higher or extended fires. However, the system reaction and ventilation strategy are almost the same regardless of the size of the fire, particularly at the beginning of the fire. Furthermore, a general evaluation of control systems and the investigation of the entire process from incident detection to system response was necessary for this experimental and numerical study. Therefore, a CFD model was developed using a fire dynamics simulator (FDS), an open-source software, for numerical simulation. Due to the relatively long length of the tunnel (5.5 km) and various safety equipment, simulating the fire and the system response was a big challenge. In such cases, simulation of the ventilation using the entire structure of the tunnel in the computational field is not easily possible, and it is not necessary. For this reason, a simplified calculation domain with a suitable boundary definition is assumed for simulation. The other required boundaries were defined using tunnel data, ambient, and tunnel conditions during the fire test. The performance of the ventilation was confirmed in smoke management in the specified schedule in the fire test. A numerical simulation was carried out to investigate the behavior of hot smoke, air velocity, and temperature distribution around the fire location.