Research on the smoke mass flow rate in one-dimensional spreading stage in tunnel with multiple fire sources

Abstract

The toxic high-temperature fire smoke plume in tunnel fire will seriously threaten the safety of personnel and tunnel structure. Therefore, it is very important to study the fire smoke plume movement law in tunnel fire for controlling and exhausting smoke. However, previous studies mainly focused on single fire source. In fact, most of the catastrophic fires have multiple fire sources. When multiple fires burn at the same time, the competitive entrainment air will cause the flame to tilt and even merge with each other, which will increase the burning rate and accelerate the spread of the fire. In this paper, the influence of fire heat release rate and distance between fires on fire smoke plume generation in tunnel is studied by a series of numerical simulations. The investigation results show that when the spacing is non-zero, the fire smoke plume generation rate is greater than that when the spacing is zero, because of the additional entrainment region. The fire smoke plume generation rate increases with HRR in spreading stage tunnel fire. In addition, a prediction model considering the heat release rate and burner edge spacing is proposed.

Keywords

• Tunnel fire
• Smoke mass flow rate
• Numerical simulation
• One-dimensional spreading stage
• Multiple fires