摘要
针对某公路隧道采用集中排烟方式的工程实际,为了分析纵向诱导风速对隧道火灾烟气控制效果的影响规律,进而确定可能的火灾场景时的合理纵向诱导风速,采用火灾动力学模拟软件FDS构建了数值分析模型,并设计了相应的火灾工况。根据隧道实际交通流量、车辆类型及公路等级,确定了模拟火灾规模。分别分析了火灾规模为50MW时隧道内不同火源位置(排烟阀打开段中部、上游1个/下游5个排烟阀、上游2个/下游4个排烟阀),不同排烟方式下(双向均衡排烟、上游端单向排烟、下游端单向排烟),不同纵向诱导风速情况时的隧道2m高处能见度、烟气蔓延范围及排烟效率,根据模拟分析结果,进而确定了不同火灾工况时的合理纵向诱导风速。结果表明:不同纵向诱导风速对集中排烟模式下烟气控制效果影响显著;特定火灾规模时,火源位置、排烟方式对合理纵向诱导风速的影响不大。
The present paper is aimed at reporting our analysis results of the affecting factors of the longitudinally induced velocity on the smoke control in highway tunnels. For our research purpose, first of all, we have introduced the engineering practice that the central smoke extraction system to be used in a highway tunnel and ways on how to identify the reasonable longitudinally induced velocities under the likely-to-be induced fire scenarios, so as to establish a numerical analysis model of the highway tunnel based on the fire dynamics simulation software FDS. And, next, we have designed an array of the corresponding fire simulation conditions and ways to determine the fire size in a tunnel according to the actual tunnel traffic flow, the vehicle types, and the highway grades. As we know, the visibility at a distance of 2m above the ground along the tunnel, the smoke spreading distance in the longitudinal direction of the tunnel, and the smoke extraction efficiency of the exhaust valves are but a few moat essential factors to be taken into account as the key evaluation indexes, except for the different longitudinally induced velocities to be taken into consideration in case of the tunnel fire involving the central smoke extraction system. Moreover, in such fire cases, it is necessary to come into mind how to deal with the problems, such as two-way balanced smoke or one-way smoke exhaust towards the upward one-way or the downward one-way exhaust, respectively. Take a 50 MW tunnel fire for example, different locations are to be taken into account if the fire is located in the central part of a tunnel, or 1 upstream exhaust inlet/5 downstream exhaust inlets or 2 upstream exhaust inlets/4 downstream exhaust inlets of the opened exhaust inlets. Based on such accounts, it would be possible to identify the reasonable longitudinally induced velocities according to the simulation results among the many choices. The results of the simulated conditions show that： the influence of different longitudinally induced velocities on the smoke control under the central smoke extraction system is of great significance. Moreover, under the specific size of fire, reasonable longitudinal induced velocities may have little difference if different exhaust modes are respectively taken or when the fires are located in different spots.
出处
《安全与环境学报》
CAS
CSCD
北大核心
2012年第5期160-164,共5页
Journal of Safety and Environment
基金
浙江省交通运输厅科技计划项目(2010H01)
灭火救援技术公安部重点试验室开放课题(KF2011003)
中南大学中央高校基本科研业务费专项资金项目(2011QNZT109)
关键词
安全工程
公路隧道
集中排烟模式
纵向诱导风速
烟气蔓延范围
排烟效率
safety engineering
highway tunnels
central smoke extraction system
longitudinal induced velocity
smokespreading distance
smoke extraction efficiency
