Study on critical wind velocity of subway bifurcated tunnel fire considering bifurcation angle and fire source location
In order to explore the influence of bifurcation angle and fire source location on the smoke spread of tunnel fire in the subway bifurcated tunnel,the fire dynamics simulation software FDS was used to study the smoke temperature distribution and critical wind velocity in the subway bifurcated tunnel under the fire scenarios of different fire source locations,fire source power and bifurcation angles.The results show that the critical wind velocity of the subway bifurcated connection tunnel is in-fluenced by the coupling effect of the coefficient α,which represents the maximum temperature rise of the ceiling,and the ve-locity loss coefficient ζ,which represents the fractional flow of the bifurcating tunnel.The temperature attenuation of smoke downstream tunnel fire source conforms to the double exponential model under the critical wind velocity.In the range of fire source power in this study,the dimensionless critical wind velocity in the bifurcating tunnel is proportional to 1/3 power of the dimensionless fire source power.Under the same fire source power,the bifurcation angle has little influence on the critical wind velocity,while the fire source location has a great influence on the critical wind velocity.The critical wind velocity be-hind the bifurcation is about 1/(1-ζ)times that in front of the bifurcation.The research results can provide a certain refer-ence for the engineering design of the ventilation and smoke exhaust system in the subway bifurcated connection tunnel.
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万方数据
维普
