The Influence To Tunnel Fires Simulation With Different Wall Boundary Condition

Since the end of 2002, our country has become the one with the most in quantity, the most complex and the fastest developed tunnels. But the larger the tunnel's scale is, the more frequently the tunnel fires will happen, once happened a fire, it is very dangerous for personnel and tunnel construction, especially for the long and large tunnels. Taking Zhongnanshan extra-long highway tunnel in Qinling as the researching object, it is analyzed how the different wall conditions affect the fire simulation in this paper in detail. And it is simulated with CFD.It becomes hot to simulate tunnel fires with CFD in the country, but most of the CFD researches simplified the tunnel model in many aspects, such as burning model, radiation model, boundary conditions and so on. It is simulated with FDS as real as possible in the paper. It is also compared the differences between those simplified and those not. It emphasis on the different settings of wall boundary conditions, and how the settings affect the smoke, the temperature, the heat transfer between the wall and smoke, etc. Based on the model established with FDS, it is analyzed how the smoke spread affected by the different ventilation modes, blockin traffic and the tunnel gradient. Through the analyses, it is given that which case is appropriate to use the simplified models, and how the tunnel ventilation affected by the blockin traffic.It is shown that the model established in the paper with quite comprehensive parameters is inosculated with the test results very well. The achieved conclusion, how the different wall condition affects the tunnel fires and the tunnel ventilation, could be referenced by the tunnel fire simulation in future, also by the tunnel fires design for the long and large tunnels.