【摘要】 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。更多还原

【Abstract】 In this paper,CFD method was applied to simulate the effectiveness of longitudinal ventilation on controlling the tunnel fire smoke diffusion with geometrical model,which was established based on certain section with actual size in Beijing metro the 4th line.The relationships between the critical ventilation velocity and the heat release rate(HRR) under different heat source conditions were studied,and then the results were compared with the other reported equations.It was presented that critical ventilation velocity was proportional to one-third power of the rate of HRR to tunnel width,and the declination angle of the heat rising plume was a constant with critical ventilation velocity.Furthermore,when the length of heat source was changed with HRR proportionally,the critical ventilation velocity was steady under high HRR condition.It was concluded that the setting of heat source had great influences on simulation results when the CFD method was used to realize the ventilation design of tunnel fire.更多还原