Study on the Spread Law of Smoke in Tunnel Fires under the Synergistic Effect of Longitudinal Ventilation and Scattered Exhaust Outlets

Abstract

Taking the Sutong Second Urban Area Expressway Tunnel as the background, this study aims to investigate the law of smoke spread in tunnel fires under the synergistic effect of longitudinal ventilation and scattered exhaust outlets. The numerical simulation method is adopted to analyze the longitudinal distribution of early-stage temperature, CO concentration and visibility during tunnel fires under different working conditions, so as to obtain the optimal smoke control strategy. When the number of scattered exhaust outlets is fixed, the higher the exhaust volume of a single scattered exhaust outlet is, the more effectively the smoke spread can be controlled. When the exhaust volume of a single scattered exhaust outlet is 10 m³/s, 20 m³/s and 30 m³/s respectively, there will be a great impact on the smoke exhaust effect, resulting in the inability to control the smoke and causing the smoke to enter the second smoke exhaust section, which poses a serious threat to the evacuation and rescue of people. When the exhaust volume is increased to 40 m³/s, after the smoke passes through the scattered exhaust outlets, it does not spread to the next smoke exhaust section, and the smoke is effectively controlled, which is conducive to the evacuation and rescue of people and will not pose a serious threat to the evacuation and rescue of people. Therefore, under specific conditions, the synergistic effect of longitudinal ventilation and scattered exhaust outlets can well control the spread of smoke.