Study On Flow And Temperature Characteristic Of Smoke In Tunnel Using Typical Ventilation Method

With the investment of infrastructure growing and transit network improved,the number of tunnel,used as parts of highway network or railway network,has increased a lot in recent years.The huge damage may be caused due to narrow space inside tunnels when fire disaster takes place.Besides,the urbanization leads to the growing number of subway line,which indirectly leads to the transfer stations being built.The smoke control of those transfer station has drawn attentions as well.Based on the background introduced before,the main research of the dissertation include:Steady numerical simulation was used to simulate existing experiment of tunnel fires.Then the simulation results and experimental results were compared to demonstrate the accuracy of numerical simulation.For tunnel fire with large heat release rate(HRR),the maximum temperature acquired by Kurioka model is different with those temperature acquired by full-scale experiments.On the basis that the accuracy of numerical simulation has been proved,the numerical simulation was then conducted to simulate the tunnel fire with large HRR.According to simulation result,the Kurioka model was modified.Through comparison of modified Kurioka model and existing results obtained by full-scale experiments,the modified Kurioka model was proved to be authentic.For the subway station with only one subway line,there is effective,specific fireproof strategies in subway station smoke-control design of China.For the subway station with more than one subway lines,the fire-proof strategies are still in discuss.Numerical simulation was used to demonstrate the effectiveness of existing smokecontrol strategies for the station that has only one subway line.Based on the issue,the paper put up a series of smoke-control strategies focusing on different fire scenario likely taking place in different areas of transfer station.Numerical simulation was conducted to verify the feasibility of those strategies.The results showed that the strategies used for upper and lower platform can successfully prevent smoke from spreading.However,due to the height of the platform floor,large regions in lower platform cannot meet the standard of safe evacuation.With the increasing volume of exhausted air,the effects of smoke-control strategy are getting better,which deseves to be taken consider into smoke-control design in actual engineering project.For the fire happening in transfer channel,the effects of two smoke-control strategies are different.Evacuation was also analyzed in the subway station with and without engineering transformation.The time spent on safe evacuation was calculated by simulation.Meanwhile,the impact of the transfer channel on evacuation was analyzed as well.The results showed the evacuation time is much relevant to the occupant density inside the subway station,which deserved more attention when it comes to crowd control.