Study on the Equivalent Width Coefficient of Tunnel Entrance in Metro Station

摘要

The numerical simulation results of 12 typical fire scenarios prove that the boundary conditions of tunnel entrance exert a significant influence on the accuracy and reliability of the fire numerical simulation results in metro station. In the fire scenarios with four 400-metre-long tunnels at both ends of the platform, the fire numerical simulation result is the most accurate, but the total numerical calculation time is twice more than the other fire scenarios, due to the additional volume of the computational meshes of the 4 tunnels. In order to guarantee the accuracy and reliability of the fire numerical simulation results on the condition that the computational mesh volume and numerical calculation time have not to be increased, 18 new fire scenarios with the different width of the tunnel entrance have been designed to simulate fire smoke movement in metro station, and the results are inserted into Lagrange's Interpolation Equation, then the equivalent width coefficient ε of tunnel entrance is found to be in the range of 0.34～0.55. In consideration of the mesh cell size and evacuation safety, ε is suggested to be 0.375.