中文摘要：

采用数值模拟的方法,对火源位于合流分岔路段上游时不同的纵向通风烟气控制策略进行了模拟分析,得到最佳的通风控制策略及送风参数。研究结果表明：火灾发生时,若只有主隧道送风,当送风风速为临界风速时,尽管火源上游烟气得到了很好的控制,但下游仍会有部分烟气会流入匝道,影响匝道内的行车安全;若加大主隧道送风风速以消除匝道内的烟气,则所需风速过大,既不经济也不安全;如果采用主隧道和匝道联合送风的送风策略,主隧道以临界风速送风,则匝道以较小的送风风速即可得到较好的烟气控制效果。该通风策略应为最优的烟气控制策略。

英文摘要：

The different smoke control strategies with longitudinal ventilation when fire source locating at the upstream of converging and diverging sections in urban underground road were simulated and analyzed by using the numerical simulation method,and the optimum ventilation control strategy and air supply parameters were obtained. The results showed that when the fire occurs,if only conducting air supply in the main tunnel,when the air supply velocity is the critical velocity,although the smoke in the upstream of fire source can be controlled well,but part of the smoke will flow into the ramp in the downstream,which may influence the traffic safety in the ramp. If increasing the air supply velocity in the main tunnel to eliminate the smoke in the ramp,the desired air velocity will be too large,which is neither economic nor safe. When adopting the air supply strategy with combined air supply both in the main tunnel and ramp,and carrying out air supply with the critical velocity in the main tunnel,the better smoke control effect can be achieved in the ramp with smaller air supply velocity,which should be the optimum smoke control strategy.