T型街谷交叉路口机动车诱导下污染物传播规律  

Numerical simulation of pollutant dispersion induced by vehicle moving in a T-shaped intersection

作　　者：苏昌榕 明廷臻[1] 吴永佳 石天豪 何芳艳 SU Chang-rong;MING Ting-zhen;WU Yong-jia;SHI Tian-hao;HE Fang-yan(School of Civil Engineering and Architecture,Wuhan University of Technology,Wuhan 430070,China)

机构地区：[1]武汉理工大学土木工程与建筑学院,湖北武汉430070

出　　处：《中国环境科学》2022年第4期1534-1544,共11页China Environmental Science

基　　金：国家自然科学基金资助项目(51778511)。

摘　　要：为了探究车辆转弯行驶对于T型街谷交叉路口处空气流动以及污染物扩散的影响,本文建立了该系统中车辆移动下空气流动与污染物传播耦合数学模型,采用计算流体力学方法,揭示T型街谷交叉路口处车辆诱导下的机械湍流特性,并且基于场协同理论量化了车速对污染物扩散的影响.结果表明,在不同速度的转弯过程中,转弯速度增加使得车辆诱导的湍动能也随之增加.车速为9m/s时车辆中轴线湍动能最大值是车速为3m/s时的5倍.但是完成转弯行驶瞬时车辆尾部湍动能的影响长度不变(约为4m).车速由3m/s增加至9m/s时,场协同数增加了66%,行人区内污染物平均浓度降低了43%.车辆转弯行驶速度增加,改变了T型街谷交叉路口处流场结构,速度场与污染物浓度场之间的协同作用增强,提高了行人区内污染物对流扩散效果,使得污染物浓度降低.In order to explore the influence of the moving vehicle on the air flow and pollutant dispersion at the T-shaped street intersection, a mathematical model coupling the fluid and pollutant concentration fields with the moving vehicle is established. The characteristics of the traffic-induced turbulence and pollutant diffusion in the T-shaped street intersection are revealed using the method of computational fluid dynamics. Based on filed synergy theory, the impact of the vehicle moving speed on pollutant dispersion is quantitatively evaluated. The results show that the turbulent kinetic energy induced by the moving vehicle increases with the increase of the vehicle speed. When the vehicle speed is 9m/s, the maximum turbulent kinetic energy on the central axis of the vehicle is 5times higher than that when the vehicle speed is 3m/s. However, the affected region of the turbulent kinetic energy in the rear of the vehicle is about 4m for all the cases. When the vehicle speed increases from 3m/s to 9m/s, the field synergy increases by 66%, and the average concentration of pollutants in the pedestrian area decreases by 43% With the increase of vehicle moving speed, the flow field at T-shaped street intersection is changed, and the synergistic effect between the velocity field and the pollutant concentration field is enhanced, which in turn reduces the pollutant concentration by improving the convective mass transfer effect in the pedestrian region.

关 键 词：T型街谷交叉路口 车辆转弯 数值模拟 污染物 场协同理论 

分 类 号：X511[环境科学与工程—环境工程]