Influence of altitude on smoke movement characteristics of train fire in tunnel rescue station
In order to investigate the influence of altitude on the smoke propagation characteristics of high-speed train entering the emergency rescue station in tunnel,a numerical simulation method of train fire in emergency rescue station in high-altitude tunnel was constructed by using three-dimensional unsteady N-S equation and RNG k-ε turbulence model with full buoyancy correction.The train movement process in tunnel was realized based on sliding grid technology.The reliability and correctness of the numerical simulation method were verified by using the existing tunnel fire dynamic model test and tunnel static fire test results.The influence of altitude on the flue gas velocity and temperature distribution in the cross passage near the accident tunnel,the rescue station and the middle carriage of the train was studied.The results show that when the train enters the tunnel emergency station,the piston wind dominates the fire smoke spreading trend.At the moment when the train stops,the peak value of flue gas velocity and temperature at the arch of the accident tunnel and the arch of the cross passage near the middle carriage of the train gradually increases with the increase of the altitude.After the train stops,the piston wind gradually attenuates,and the smoke starts to counter current upstream to the fire source at the tunnel vault.With the increase of altitude,the spread range of the high temperature area in the downstream of the emergency rescue station gradually expands,and the peak temperature at the tunnel vault increases accordingly.The difference between the peak temperature of the tunnel arch at high altitude and low altitude gradually increases with time,which may cause greater threat to the safety of personnel in the rescue station of the tunnel at higher altitude.At different altitudes,the temperature at the height of human eyes in the cross passage near the middle carriage of the train exceeds 330 K(harmful to human body),and at the same time,the higher the altitude,the lower the height of the high temperature smoke layer in the cross passage,and the smoke settlement speed is significantly accelerated.
high altitudetrain firetunnel emergency rescue stationsmoke spread
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