排烟风量变化对隧道集中排烟效率的影响  

Influence of exhaust rate change on extraction efficiency of central smoke extraction system

作　　者：刘琪[1,2] 姜学鹏[1] 蔡崇庆[3] 袁月明[1] 

机构地区：[1]中南大学土木工程学院,长沙410075 [2]湖南中医药大学人文社科学院,长沙410208 [3]中铁第四勘察设计院集团有限公司城市轨道与地下工程设计研究院,武汉430063

出　　处：《安全与环境学报》2012年第6期177-180,共4页Journal of Safety and Environment

基　　金：湖南省科技计划项目(2012GK3169);灭火救援技术公安部重点实验室开放课题(KF2011003);中南大学中央高校基本科研业务费专项资金项目(2011QNZT109)

摘　　要：隧道集中排烟系统的排烟风量是影响火灾烟气抽排效果的关键参数。量化评价烟气抽排效果有利于排烟风机的优化选型。基于FDS的火灾燃烧过程的化学反应式得到隧道火灾烟气的质量生产速率,提出了排烟效率和排烟效能两个表征集中排烟系统烟控能力的计算公式。用基于大涡模拟的FDS软件对隧道火灾烟气进行数值模拟计算。对比研究表明,随着排烟风量的增大,机械排烟效率增大,机械排烟效能反而降低。风机排烟风量增大使多个排烟阀处发生吸穿现象,但风流短路并未降低整个排烟系统的排烟效率。根据研究结果给出了合理的风机排烟风量设计区间,确定三阳路道路隧道集中排烟系统的最佳排烟风量为170m3/s,对应的排烟效率为96.3%。Central smoke extraction system is gradually becoming the mainstream in the field of tunnel emergency ventilation design. Ex- haust rate is key design parameter of central smoke extraction system, which determines the effectiveness of smoke control. How to quantita- tively evaluate fire smoke control is a subject worthy of study. Based on mixture fraction combustion model used in FDS, mass flow rate of fire smoke was obtained. Smoke extraction efficiency formula and ex- traction benefit-cost ratio formula were put forward, which can reveal the extraction abilities of central smoke extraction system. Fire Dy- namics Simulation is employed to run numerical simulations based on Sanyang road cross-river tunnel. We have laid out fifteen different ex- haust rates at a heat-releasing rate of 20 MW. The interval between the two exhaust posts is sixty meters. By analyzing the simulation re- suits, a conclusion can be made; by increasing exhaust rate can pro- mote the smoke extraction efficiency. Nevertheless, after the exhaust rate reaches a certain value, the extraction efficiency would keep constant, and extraction benefit-cost ratio can quickly be reduced. Two-way central smoke extraction system, for smoke shafts located at both ends of road tunnel, would result in unbalanced suction force in different locations on exhaust ports. The smoke layering plug holing is easy happen in multi-exhaust ports. For several exhaust ports which opened to extract smoke at the same time, the short circuit of the flow did not lower the extraction efficiency of central smoke extraction sys- tem efficiency. This phenomenon is different from single exhaust port. In this study, a reasonable exhaust rate scope of design was presented. The optimal exhaust rate of central smoke extraction sys- tem is 170 mS/s at a heat releasing rate of 20 MW, the corresponding extraction efficiency is 96.3 %.

关 键 词：安全工程 公路隧道 风机排烟风量 排烟效率 集中排烟系统 

分 类 号：U453.5[建筑科学—桥梁与隧道工程]