沉管隧道内车厢火羽流的临界风速研究  

Study on critical ventilation velocity induced by ejected fire of carriage in immersed tunnel

作　　者：唐飞[1] 刘紫玮 孙协鹏 刘帅[2] 徐童 TANG Fei;LIU Ziwei;SUN Xiepeng;LIU Shuai;XU Tong(State Key Laboratory of Fire Science,University of Science and Technology of China,Hefei Anhui 230027,China;China Merchants Chongqing Communications Technology Research&Design Institute Co.,Ltd.,Chongqing,400067,China;Institute of Disaster Prevention Science and Safety Technology,Central South University,Changsha Hunan 410075,China)

机构地区：[1]中国科学技术大学火灾科学国家重点实验室,安徽合肥230026 [2]招商局重庆交通科研设计院有限公司,重庆400067 [3]中南大学防灾科学与安全技术研究所,湖南长沙410075

出　　处：《中国安全科学学报》2023年第2期75-81,共7页China Safety Science Journal

基　　金：国家重点研发计划项目(2022YFC3005201);国家自然科学基金资助(52076066,52211530053);重庆市自然科学基金资助(cstc2021jcyj-msxmX1052)。

摘　　要：为探究纵向通风与侧向集中排烟协同作用下,沉管隧道内车厢火羽流的临界控制风速特征,首先,建立1∶8缩尺寸隧道试验模型;然后,选取3种车厢开口尺寸及9组火源功率,并考虑侧向集中排烟系统开启和关闭2种状态,采集沉管隧道内不同纵向风速下顶棚烟气温度数据;同时,通过火灾动力学模拟软件(FDS)模拟沉管隧道内车厢火羽流的速度场和温度场分布特征;最后,分析临界风速演化的物理影响机制。结果表明:无论侧向集中排烟系统是否开启,隧道顶棚下方烟气最大温升均会随纵向风速增加而下降,同时隧道内烟气逆流长度也会不断缩短直至为0;随隧道内车厢火源功率的增加,临界风速均呈现先增大后不变的趋势;在相同火源功率条件下,侧向排烟系统开启时对应的临界风速明显大于其关闭的情况;在侧向排烟与纵向通风协同作用下,随火源功率增加,沉管隧道车厢火羽流临界风速呈现先增加、后不变的分段函数关系。For studying the critical velocity characteristics of smoke control induced by carriage fire plume under the synergy effect of longitudinal ventilation and lateral concentrated smoke extraction in immersed tunnel,a 1∶8 reduced-scale test model was firstly established.Based on 3 carriage opening sizes,9 fire heat release rates and 2 states(on and off)of lateral smoke exhaust system,the smoke temperature under the immersed tunnel ceiling with different longitudinal velocity was collected.Meantime,the distribution characteristics of velocity and temperature field of ejected fire in immersed tunnel were simulated by FDS(Fire Dynamics Simulator).Finally,the physical influence mechanism of critical velocity evolution was analyzed.The results show that whether the lateral concentrated smoke extraction system is open or not,the smoke maximum temperature under ceiling decreases significantly,and the smoke back-layering length continues to shorten with the increasing longitudinal velocity.Moreover,the critical velocity shows the increasing section firstly and then remains unchanged trend with the increasing fire heat release rate of carriage fire in tunnel.Under the synergetic effect of lateral smoke exhaust and longitudinal ventilation,the critical velocity of carriage fire in immersed tube tunnel increases with the increasing heat release rate,which shows a piecewise function relationship of first increasing,then unchanged.

关 键 词：沉管隧道 车厢火羽流 临界风速 纵向通风 侧向集中排烟 

分 类 号：X928.7[环境科学与工程—安全科学]