Experimental Research On Fire Smoke Control Of Railway Tunnel Rescue Station Considering Piston Wind

With the in-depth development of the national railway construction,there are already many extra-long railway tunnels in operation,and in the future,more extra-long railway tunnels will be built.When the length of a railway tunnel is more than 20 km,it is necessary to set up rescue stations.In the extra-long railway tunnel rescue station,the control of fire smoke is a key factor to ensure that the evacuation of people can proceed smoothly.At present,the related research mainly considers the situation that the fire source is stationary,and cannot truly reflect the distribution of wind speed field and the spread of smoke within the rescue station.In this paper,a model test platform for the train-piston wind coupling action of the extra-long railway tunnel rescue station was established,the distribution of wind velocity field and the spread of smoke in the rescue station of the extra-long railway tunnel considering the effect of piston wind were studied and a reasonable smoke control strategy was proposed.The numerical simulation results and model test data were compared and analyzed combined with computational fluid dynamics simulation software.The main findings are as follows:(1)Based on the basic principles of fluid mechanics and similar theories,the similarity rule of wind velocity field in extra-long railway tunnels was deduced.A model test platform for the train-piston wind coupling action of the extra-long railway tunnel rescue station was designed and established by Euler number and Strouhal number.(2)The experimental study on the distribution of the wind speed field at the rescue station while the train was running in a tunnel was carried out.Through comparative analysis,the influences of the train speed,the train length and the position of the train stop on the distribution of the wind speed field at the rescue station were studied.The influence of different factors on the wind speed field at the rescue station considering the effect of piston wind was obtained.(3)The experimental study on the spread of smoke at the rescue station of the extra-long railway tunnel under fire conditions was carried out,and the law of spread of smoke at the rescue station and the smoke control strategy were obtained.The result shows that under the condition of free spread,the two transverse alleyways closest to the fire source along the direction of the driving would be quickly invaded by smoke.When the axial fans at both ends of the parallel tunnel were opened and the wind speed was large enough,the smoke could be effectively inhibited from spreading into the transverse alleyway,and the safety of evacuation of people could be ensured.(4)FLUENT three-dimensional dynamic mesh function was used to model and simulate the experimental model.Comparing the numerical simulation results with the model test data,the results proved the reliability of the in-depth study of related issues by numerical simulation methods.