Simulation of Large-Scale Tunnel Belt Fire and Smoke Characteristics under a Water Curtain System Based on CFD

Transport belt fires pose a serious threat to the lives of miners. The smoke spread characteristics of transport belt fires are important for the effective construction of underground safety works. In this paper, a water curtain system is added to ventilation to investigate the effectiveness of water spray in blocking fire-induced smoke and heat. Using computational fluid dynamics (CFD) simulations obtained with FDS 6.0.1, full-scale underground belt transport tunnel fire tests are conducted with mechanical ventilation and a water curtain system to obtain smoke spread characteristics, temperature distribution, visibility profiles, and CO distribution. The results show that the addition of a water curtain system can effectively limit temperature and smoke, but high mechanical ventilation velocities are not conducive to the water curtain system, limiting underground tunnel fires. This study found that the mechanical ventilation velocity should be controlled at approximately 0.8 m/s when the water curtain system is on a 100 m beltway. Smoke across the water curtain system area, smoke stratification in the lower layer of the water curtain area is lost, the water curtain system in the lower layer of the tunnel will affect the flow field and temperature field flowing to the fire source, and the blockage effect is the most obvious in the upper layer of the tunnel. The water curtain system reduces the distribution of temperature and CO concentration in the tunnel and rapidly restores visibility. With the addition of the water curtain system, the environment in the restricted area is suitable for occupant evacuation and firefighting, and the system can be considered a viable strategy for tunnel smoke control.