中文摘要：

以某典型“十”字交叉换乘地铁车站为研究对象，通过数值模拟的方法对换乘车站两站台同时发生火灾的极端情况下不同排烟方案的排烟效果进行了研究，方案1是站厅层送风，地下二层和三层站台分别排烟；方案2是在方案1的基础上，将地下三层的车站屏蔽门打开，利用车站隧道风机进行辅助排烟．火源设计为峰值2MW的时间平方快速火．研究结果表明：两种方案都能有效控制地下二层站台烟气蔓延，方案2中打开地下三层车站屏蔽门，利用车站隧道系统辅助排烟的措施可以有效增加楼梯处的向下风速，同时降低楼梯处烟气温度，延长火源附近楼梯作为人员疏散通道的时间，实现良好的换乘站防烟效果．

英文摘要：

The effect of smoke control for a multi-source fire scenario in a cross-type interchange subway station had been investigated by the numerical method in this paper. Two fires occard at the same time on the second and third underground floor. The fires were designed as fast Q-t2 fire with the peak heat release rate of 2 MW. Two types of fire emergency ventilation modes were selected. Air was supplied on the first lobby floor and smoke was exhausted on both second and third underground floor in these two ventilation modes. The difference between the two modes was whether the tunnel smoke exhaust system on the third floor was operating. Numerical results show that smoke is controlled effectively on the second underground floor in both modes. Combing the underground third floor with tunnel ventilation system by opening PSD can increase the downward air flow velocity and decrease the air temperature at staircases near the fire. Time during which the staircase near fire can be used for evacuation is increased. Good smoke control effect for interchange station can be got.