Abstract:

Single hole tunnel model was established and the influence of the combined baffles on the mechanical exhaust of the tunnel was analyzed by FDS.The results showed that compare to the normal smoke exhaust port, the installation of combined baffles can effectively improve the mechanical exhaust efficiency of the tunnel, improve the distribution of the gas pressure field at the exhaust vent, reduce the vertical exhaust air velocity, and increase the horizontal smoke exhaust wind speed, thereby reducing the probability of occurrence of plug-holing. Through simulation verification, it is found that the height of the combined baffles is an important factor affecting the occurrence of plug-holing. The combined baffles will make the thickness of the smoke layer in front of the smoke exhaust port smaller, and the plug-holing will occur when the thickness of the smoke layer is less than the height of the baffle. By comparing the simulation results of the baffle heights of 50, 65, 80, 95, 110 cm, it is found that the flue gas concentration at the exhaust vent is the highest when H=50 cm, the smoke exhaust per unit time is the largest, and the smoke exhaust effect is the best.  

Key words: tunnel fire, smoke control, numerical simulation;combined baffles