倾斜隧道火灾烟气分层稳定性研究  

Study on smoke stratification stability in inclined tunnel fire

作　　者：孙超鹏 刘方 翁庙成 Sun Chaopeng;Liu Fang;Weng Miaocheng(College of Civil Engineering,Chongqing University,Chongqing 400000,China)

机构地区：[1]重庆大学土木工程学院,重庆400000

出　　处：《消防科学与技术》2024年第9期1227-1233,共7页Fire Science and Technology

基　　金：国家自然科学基金(52178064);重庆市技术创新与应用发展专项(CSTB2022TIAD-KPX0101);重庆市建设科技项目(城科字2021第5-8)。

摘　　要：隧道内的烟气分层特征对分析疏散和救援的难度以及制定有效的应急策略具有至关重要的作用。倾斜隧道中的烟气流动受到浮力和烟囱效应的共同影响,导致烟气的分布和运动规律与水平隧道存在显著差异。在倾斜隧道中,烟气分层稳定性受到多种因素的影响,且相关研究较少。本文采用数值模拟方法对倾斜角度为1%~15%的两端开口的倾斜隧道火灾烟气分布特性及其影响因素进行了研究。研究表明:Newman提出的判定烟气分层状态的临界无量纲温差在倾斜隧道火灾中仍然适用(坡度在1%~15%范围内)。倾斜隧道火灾发生后,火源与低端入口之间的烟气层始终能够保持稳定的烟气分层。而火源与下游出口之间的烟气层则随着烟囱效应的增强,稳定分层被破坏的区域不断扩大,并逐渐扩展至整个下游区域。火源功率和火源与下游出口之间的高差可直接影响隧道内的烟囱效应和烟气自身浮力,进而影响烟气分层状态。在此基础上,提出了用于预测倾斜隧道火灾烟气分层特性的计算模型,并确定了烟气分层区域1和区域2之间的临界Froude数为0.9。本文研究可为隧道火灾排烟及疏散设计提供指导。The smoke stratification characteristics in the tunnel play an important role in analyzing the difficulty of evacuation and rescue and formulating effective emergency strategies.The smoke flow in inclined tunnels is affected by both buoyancy and stack ef-fect,resulting in significant differences in the distribution and movement of smoke between inclined tunnels and horizontal tun-nels.In inclined tunnels,the stability of smoke stratification is af-fected by many factors,and there are few related studies.In this paper,the numerical simulation method is used to study the smoke distribution characteristics and its influencing factors of in-clined tunnel fires with openings at both ends with an inclination angle of 1%~15%.The research shows that the critical dimen-sionless temperature difference proposed by Newman to deter-mine the stratification state of smoke is still applicable in inclined tunnel fires(the slope is within the range of 1%~15%).After the fire in the inclined tunnel,the smoke layer between the fire source and the low-end entrance can always maintain a stable smoke stratification.The smoke layer between the fire source and the high-end outlet increases with the chimney effect,and the area where the stable stratification is destroyed continues to expand and gradually expands to the entire downstream area.The fire source power and the height difference between the fire source and the high-end outlet can directly affect the stack effect in the tunnel and the smoke buoyancy,thus affecting the smoke stratifi-cation state.On this basis,a calculation model for predicting the smoke stratification characteristics of inclined tunnel fires is pro-posed,and the critical Froude number between zone 1 and zone 2 is determined to be 0.9.The research conclusions can provide use-ful reference for tunnel fire smoke exhaust and evacuation design.

关 键 词：倾斜隧道 烟气分层 烟囱效应 Froude数 

分 类 号：X932[环境科学与工程—安全科学] TU998.1[建筑科学—市政工程]