Abstract: The adaptability of ventilation and smoke exhaust parameters in urban railway rescue stations under fire conditions is insufficient. To address this challenge and to improve both the safety and economy of the ventilation and smoke exhaust system, a systematic optimization study is conducted on the smoke control performance of urban railway rescue stations considering the significant differences between urban and high-speed railways in terms of disaster prevention and ventilation strategies. Based on the fire dynamics simulator, a three-dimensional numerical model is established with the C-type urban train and the Shanghai Express tunnel section as prototypes. The study adopts the “centralized smoke exhaust+non-incident tunnel make-up air” ventilation mode, analyzing the effects of key parameters such as wind speed at connecting door and tunnel supplementary wind speed. In combination with the Code for Design of Railway Tunnel Disaster Prevention, Evacuation and Rescue Engineering (TB 10020-2017) and the ASET≥RSET principle, smoke propagation patterns, visibility variations at critical sections, and safe evacuation times are investigated. Grid independence analysis is performed to ensure model reliability, and Z=2.5 m is defined as the key monitoring height for breathing level. A coupled analysis system of “parameters-smoke-evacuation” is then established. The results indicate that: (1) When the wind speed at connecting door is not less than 0.7 m/s and the tunnel supplementary wind speed is not less than 1.0 m/s, smoke does not spread into the nonincident tunnel within the 555 s evacuation time, and the visibility of key areas meets safety requirements. (2) At a wind speed at connecting door of 0.5 m/s, evacuation time is insufficient, and when the tunnel supplementary wind speed is below 0.8 m/s, effective smoke control cannot be achieved. (3) The calculated smoke exhaust volume is 95.2 m³/s, which is only 63.7% of the value specified in the code, effectively reducing the size of electromechanical and civil systems without compromising safety.

Key words: urban railway, smoke extraction, wind speed at connecting door, tunnel supplementary wind speed, Fire Dynamics Simulator, safe evacuation