Design Method of Ventilation and Smoke Exhaustion Against Urban Traffic Link Tunnel Fire

The Urban Traffic Link Tunnel(UTLT) is a new type of underground transportation,with quite a few entrances to underground garages.It is more complicated to design the ventilation and smoke exhaustion for the UTLT than for a general urban straight tunnel.According to the structural features of the UTLT,the design method of ventilation and smoke exhaustion against UTLT fire is presented.The UTLT is regarded as an independent structure apart from adjacent underground garages in cases of fire.According to the layout of the ventilation shafts and the ground access,the UTLT is divided into multiple smoke control sections by the fire roller shutters.The fire smoke flows out of the ground following the travel direction in the limited smoke control zones.An UTLT is taken as an example,with eight sections and three smoke exhaust patterns.The smoke control effect of typical fire scenarios is simulated by FLUENT.The results show that the smoke is limited to the flow in the setting smoke control sections and can be exhausted out of the tunnel.And there is no back-layering flow of hot smoke,which can satisfy UTLT ventilation requirements and ensure the safe escape for people in the upstream of the fire and the vehicles in the downstream.So the design method of ventilation and smoke exhaustion against the UTLT fire is reasonable.The research results can be applied directly to the design of ventilation and smoke exhaustion for UTLTs.