Experiment and Numerical Simulation on Smoke Characteristics of Double-Fire Sources Tunnel

Based on the serious hazards of multiple-fire source accidents in tunnels, this paper investigates the characteristics of fire smoke in the case of double-fire source accidents in tunnels. By conducting a double-fire source scale-down test in the plain area, the effects of fire source spacing and longitudinal ventilation speed on the temperature in the tunnel vault of a double-fire source are investigated; By conducting a full-size numerical simulation with FDS software, the effects of altitude and longitudinal ventilation speed on the temperature evolution and critical velocity inside a double-fire source tunnel are investigated. The results show that: As the spacing of the double-fire source increases, the longitudinal decay of the smoke temperature rise downstream of the tunnel slows down, and the maximum temperature of the vault decreases, the longitudinal temperature decay model downstream of the double-fire source and the prediction model of the maximum temperature of the vault of the double-fire source are established. In the event of a fire at low or high altitude, longitudinal ventilation reduces the maximum temperature in the vault of a double-fire source. With the increase of altitude, the maximum temperature of the vault of the double-fire source increases, the critical wind speed of the double-fire source increases, while the maximum temperature at the characteristic height of the human eye of the double-fire source decreases. The empirical formula of the critical velocity of the double-fire source at different altitudes is established.