A Prediction Model for Ceiling Temperature in the Ultra-Wide Road Tunnel Fire with Lateral Smoke Exhaust

Abstract

ABSTRACT Ultra-wide road tunnel plays an important role in relieving traffic pressure. The lateral smoke exhaust system was used to control the fire smoke in the ultra-wide road tunnel. This study conducted a series of experiments in a 1:20 scale tunnel to explore the effects of lateral smoke exhaust volume and heat release rate (HRR) on the ceiling temperature in the ultra-wide road tunnel. The results demonstrate that the ceiling temperature in the ultra-wide road tunnel with the lateral smoke exhaust is obliquely distributed along the longitudinal direction, which is different from the other smoke exhaust modes. The lateral smoke exhaust system can create a better evacuation environment for the tunnel space near the exhaust duct. As the HRR increases or the lateral smoke exhaust volume decreases, the ceiling temperature decays more slowly along the longitudinal direction of the tunnel. Finally, a longitudinal attenuation prediction model of the ceiling temperature is proposed based on a nondimensional analysis. The prediction model conforms to a double exponential function and is suitable for ultra-wide road tunnels with lateral smoke exhaust. Therefore, the research results of this study can provide references for ultra-wide road tunnel fire research and the design of lateral smoke exhaust systems.