Study On Flue Gas Spread And Temperature Distribution Characteristics Of Tunnel Fire Under Blocking Effect

As China's urbanization process to speed up the urban population more and more,urban transport system to withstand the pressure is also getting higher and higher.In order to alleviate the traffic pressure,reduce traffic congestion,many cities in China began to subway construction.Due to the particularity of the subway structure,in the subway tunnel tunnel in the event of fire,can easily lead to group death accident and major economic losses.At present,the study of subway tunnel fires is mostly for no slope tunnels,regardless of the impact of train congestion.In practice,the slope and the blocking effect can not be ignored.Based on this situation,to determine the content of this paper.In this paper,a simulation model was established based on the train fire in the actual interval tunnel(the blocking ratio is 50%).The FDS simulation software was used to simulate the fire in the middle of the train or in the end of the train,and the trains stopped at the horizontal or different slope(1%,2%,3%)of the tunnel within the dynamic flue gas flow field and temperature field.The simulation results are compared with the results of the scale model test,and the correctness of the model is verified.The influence of the slope on the flue gas spread characteristics of the tunnel and the temperature distribution along the tunnel roof temperature,the maximum temperature of the tunnel and its appearance are analyzed.The fire in the middle of the train and the left side of the train when the fire,the tunnel smoke spread law,and under different conditions,the left or right side of the train 2m,the height of the temperature changes and changes in CO concentration;analysis of fire source heat release rate(0 m / s,1 m / s,2 m / s)on the flue gas spalling characteristics and roof temperature distribution in different tunnels.It is found that the longitudinal ventilation velocity has a significant effect on the temperature distribution under the roof.When the fire source is located at the left end of the train,the flue gas is partially settled down due to the non-obstruction on the left side of the fire source.The effect of the maximum temperature on the roof and its appearance is also different.