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本文根据北京地铁4号线某段隧道的实际尺寸建立了几何模型,针对该模型利用CFD方法模拟了纵向通风对控制火灾烟气扩散的作用,研究了不同热源形状条件下临界通风速度与热释放率的关系,并将其与已有研究成果进行了对比。结果显示在热源形状不变时,临界通风速度与热释放率(HRR)和隧道宽度之比的1/3次方成正比,热羽流在临界通风速度下倾斜角为常数;当热源长度随热释放率成比例变化时,临界通风速度在高热释放率条件下呈现出稳定不变的趋势。研究表明在采用数值模拟方法进行隧道火灾通风设计时,热源条件的设置对模拟结果有显著影响。
In this paper, a geometric model is established according to the actual size of a section of tunnel in Beijing Subway Line 4. The CFD method is used to simulate the effect of longitudinal ventilation on the control of fire smoke diffusion. The effects of critical ventilation velocity and heat release Rate of the relationship, and compared with the existing research results. The results show that the critical ventilation rate is proportional to 1/3 of the ratio of heat release rate (HRR) to tunnel width when the shape of heat source is constant, and the inclination angle of thermal plume at critical ventilation speed is constant. When the length of heat source When the heat release rate changes proportionally, the critical ventilation velocity shows a steady trend under the condition of high heat release rate. The research shows that the setting of the heat source conditions has a significant effect on the simulation results when using the numerical simulation method for tunnel fire ventilation design.