Study on Optimization of Semi-lateral Ventilation Mode of Fire in the Nantong Seyuan Road Tunnel

The fire field simulation tool FDS is used to simulate and compare the different fans operating conditions of the semi-transverse ventilation of the proposed Nantong Seyuan Road Tunnel. The fire source is located at the most unfavorable position of the main road and the ramp. The heat release rate is 20 MW and the grid size is 0.2 m. Considering the natural wind speed of 1 m / s and 2 m / s, the air volume of the single fan is 20 m³ / s. The results showed that: (1) The flue gas temperature at the ceiling above the fire sources of all conditions was significantly higher than 100 ℃; when from the fire source area more than 10 m, the CO concentration was not more than 100 ppm and the height of the smoke layer was more than 2 m; (2) Opening the air feed fans was not conducive to reduce the flue temperature at the safe height. (3) Increasing the number of exhaust fans on both sides of the fire source was conducive to flue gas emissions; (4) when the exhaust fans were turned on, the addition of the ramp jet fan can not be significantly to reduce the flue gas temperature at the ramp. The aim of this study is to provide a theoretical basis for the optimization of the semi-transverse ventilation model of the fire in the Nantong Seyuan Road Tunnel.