不同集中排烟量对隧道火灾烟气控制效果的影响

 以钱江水下盾构隧道为研究对象,采用FDS 5.0对双向均衡排烟模式和50MW火灾规模下、10个不同集中排烟量对隧道火灾烟气控制效果的影响进行模拟计算。对比分析不同集中排烟量下,隧道内排烟阀处竖向排烟风速、排烟阀及排烟风机口处温度、排烟效率、行车道2m高度处能见度、烟气蔓延范围的变化情况。模拟分析表明,集中排烟量对排烟效果影响很大。当排烟量为190m³/s时,可达到较好的隧道火灾烟气控制效果。

Effect of Different Exhaust Rates on Fire Smoke Control in a Shield Tunnel

Taking Qianjiang shield tunnel as the research object and based on the CFD simulation method, a large eddy simulation analysis software FDS is adopted to simulate and analyze the effect of exhaust rate on fire smoke control under the condition of the same heat release rate of 50MW and exhaust ports in a road tunnel. Ten different exhaust rates are simulated under the mode of bidirectional equilibrium smoke extraction. Comparative analysis are made on smoke flow velocity in exhaust ports, temperature at exhaust ports and exhaust fans, smoke exhaust efficiency, visibility distributions at two meters high of road, and smoke spread distance, when smoke exhaust rates are different. The results show that different smoke exhaust rates have great influence on smoke exhaust effect. The simulation results show that smoke flow velocities in exhaust ports are less than 10m/s, temperature at exhaust fans are less than 280℃, and visibility distributions at two meters high of road are more than 10m, which satisfy requirements of the design code. When the smoke exhaust rate are greater than or equal to 190m³/s, the temperature at exhaust ports is less than 280℃, smoke exhaust efficiency could reach at 100% and fire smoke is limited in the section of the opened exhaust ports. It is indicated that a quite good smoke control effect could be achieved. The results could provide some reference to design institutes for selecting exhaust fan.