摘要
通过隧道的车辆会排放尾气污染物,影响隧道内环境和工作人员的身体健康。为了更好的掌握特长隧道中汽车尾气的流动运移规律,提高特长隧道通风系统的排污效率,改善特长隧道内环境,运用商业软件Fluent,用RNG k-ε模型,结合Layering(动态层模型)的动网格技术,以CO作为尾气污染物,分析了特长隧道内瞬态汽车尾气的扩散特征,研究了不同车距及不同行驶速度下特长隧道内汽车尾气的流动规律。模拟结果表明:在车尾回流的作用下,CO污染物分布都有形成旋涡的趋势,且长车距或者车后没有其他车辆以及车辆低速行驶时,更易形成旋涡状分布;行车速度越大湍流动能(TKE)和车辆周围气流速度也越大;在一种行驶速度下车后湍流动能大的位置由于气流扰动明显,气流速度会降低,高湍流强度还会稀释污染物使高湍流动能处的CO含量降低;短时间内CO主要分布范围在车辆高度2 m附近,长车距下不同车速的CO含量分布规律相似,但短车距下后方汽车的存在会则影响前方车辆排出的CO分布,使其扩散速度减慢。本研究可以为特长隧道通风系统提供研究基础。
Vehicles passing through the tunnel will emit exhaust pollutants,which will affect the environment in the tunnel and the health of the staff.In order to better grasp the flow and movement of automobile exhaust gas in the extra-long tunnel,improve the blowdown efficiency of the extra-long tunnel ventilation system,and improve the environment in the tunnel,this study using the commercial software Fluent,adopting the RNG k-εmodel,and combining the dynamic grid technology that Layering(dynamic layer model),uses CO as the exhaust pollutant to analyze the diffusion characteristics of transient automobile exhaust in the extra-long tunnel.The flow law of automobile exhaust in the extra-long tunnel in different vehicle distances and different driving speeds were studied.The simulation results show that the distribution of CO has a tendency to form a vortex influenced by backflow.Besides,the vortex-like distribution is more likely to form when the vehicle distance is long,there are no other vehicles behind the vehicle,and the vehicle is driving at a low speed;the greater the driving speed,the Turbulent Kinetic Energy and the air velocity around the vehicle are also greater.At the same driving speed,a position where the Turbulent Kinetic Energy is large will be reduced air velocity due to the obvious airflow disturbance.The high Turbulent Kinetic Energy will also dilute the pollutants and reduce the CO concentration;the main CO distribution range in the vehicle height of 2 m during short time nearly,the distribution of CO at different speeds under long distances is similar,but the existence of rear cars under short distances will affect the distribution of CO emitted by the vehicles in front and slow down the diffusion speed.This research can provide a study foundation for extra-long tunnel ventilation system and better guide the layout of extra-long tunnel ventilation system.
作者
任涛
陈结
刘戎
周云
刘丹
Ren Tao;Cen Jie;liu Rong;Zhou Yun;Liu Dan(Chongqing Traffic Engineering Quality Inspection Co.,Ltd.,Chongqing 400067,P.R.China;State Key Laboratory of Coal Mine Disaster Dynamics and Control,Chongqing University,Chongqing 400044,P.R.China;School of Resources and Safety,Chongqing University,Chongqing 400044,P.R.China)
出处
《地下空间与工程学报》
CSCD
北大核心
2022年第S02期1008-1014,共7页
Chinese Journal of Underground Space and Engineering
基金
重庆市自然科学基金(cstc2020jcyj-msxmX1076)
国家自然科学基金(51774057)
关键词
数值模拟
汽车尾气
污染物分布
动网格
numerical simulation
automobile exhaust
pollutant distribution
dynamic grid
作者简介
任涛(1983—),男,河南荥阳人,博士生,主要从事岩土工程检测设计方面的研究。E-mail:57662097@qq.com;通讯作者:陈结(1984—),男,湖南邵阳人,博士,教授、博士生导师,主要从事岩土工程方向研究。E-mail:jiechen023@cqu.edu.cn
