Abstract：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.
苏昌榕, 明廷臻, 吴永佳, 石天豪, 何芳艳. T型街谷交叉路口机动车诱导下污染物传播规律[J]. 中国环境科学, 2022, 42(4): 1534-1544.
SU Chang-rong, MING Ting-zhen, WU Yong-jia, SHI Tian-hao, HE Fang-yan. Numerical simulation of pollutant dispersion induced by vehicle moving in a T-shaped intersection. CHINA ENVIRONMENTAL SCIENCECE, 2022, 42(4): 1534-1544.
王乐,张云伟,顾兆林.动态风场及交通流量下街道峡谷内污染物扩散模拟[J]. 中国环境科学, 2012,32(12):2161-2167. Wang L, Zhang Y W, Gu Z L. The numerical simulation of pollutant dispersion in street canyons under dynamic wind field and traffic flux conditions[J]. China Environmental Science, 2012,32(12):2161-2167.
[2]
杨方,钟珂,亢燕铭.街道峡谷对称性对污染物扩散的影响[J]. 中国环境科学, 2015,35(3):706-713. Yang F, Zhong K, Kang Y M. Effects of street geometric configurations on the pollutant dispersion around the canyons[J]. China Environmental Science, 2015,(3):706-713.
[3]
陈晓萌,亢燕铭,杨方,等.上游阻挡建筑间距对街谷内空气环境的影响[J]. 中国环境科学, 2016,36(7):1967-1973. Chen X M, Kang Y M, Yang F, et al. Impact of the distance between the upstream buildings and the street canyon on the air environment in the street canyons[J]. China Environmental Science, 2016,(7):1967- 1973.
[4]
钟珂,亢燕铭,王翠萍.城市街口规划设计与城市空气环境的关系[J]. 中国环境科学, 2001,(5):77-80. Zhong K, Kang Y M, Wang C P. Relationship between street corner design in urban plan and urban air environment[J]. China Environmental Science, 2001,(5):77-80.
[5]
Cai C, Ming T, Fang W, et al. The effect of turbulence induced by different kinds moving vehicles in street canyons[J]. Sustainable Cities and Society, 2020,54:102015.
[6]
张云伟,王晴茹,陈嘉,等.城市街谷内PM2.5浓度时空变化及影响因素分析[J]. 中国环境科学, 2016,36(10):2944-2949. Zhang Y W, Wang Q R, Chen J. Temporal and spatial characteristics of PM2.5 concentration in urban street canyons and analysis on the affecting factors[J]. China Environmental Science, 2016,(36):2944- 2949.
[7]
田丰,余志,蔡铭,等.双车道街道峡谷内污染物扩散的模拟[J]. 中国环境科学, 2007,(5):604-607. Tian F, Yu Z, Cai M, et al. Modelling of pollutant dispersion in double-lane street canyons[J]. China Environmental Science, 2007, (5):604-607.
[8]
李政桐,蔡存金,黄晓明,等.深街道峡谷内高架桥对污染物传播特性影响的模拟研究[J]. 环境科学研究, 2018,31(2):254-264. Li Z T, Cai C J, Huang X M, et al. Numerical simulation on the effect of viaduct settings on the air flow and pollutants dispersion in the deep street canyon[J]. Research of Environmental Sciences, 2018,31(2):254-264.
[9]
Tomlin A S, Smalley R J, Tate J E, et al. A field study of factors influencing the concentrations of a traffic-related pollutant in the vicinity of a complex urban junction[J]. Atmospheric Environment, 2009,43(32):5027-5037.
[10]
黄远东,王梦洁,钱丽冰,等.T型街道内空气流动与污染物扩散特性研究[J]. 环境污染与防治, 2019,41(3):257-260,265. Huang Y D, Wang M J, Qian L B, et al. Investigation of airflow and pollutant dispersion in T type street canyon[J]. Environmental Pollution & Control, 2019,41(3):257-260,265.
[11]
Chang C H, Meroney R N. Concentration and flow distributions in urban street canyons:wind tunnel and computational data[J]. Journal of wind engineering and industrial aerodynamics, 2003,91(9):1141- 1154.
[12]
Robins A, Savory E, Grigoriadis S D. Spatial variability and source-receptor relations at a street intersection[J]. Water, Air, & Soil Pollution:Focus, 2002.
[13]
Yassin M F, Kellnerova R, Janour Z. Impact of street intersections on air quality in an urban environment[J]. Atmospheric Environment, 2008,42(20):4948-4963.
[14]
Nosek Š, Kukačka L, Jurčáková K, et al. Impact of roof height non-uniformity on pollutant transport between a street canyon and intersections[J]. Environmental Pollution, 2017,227:125-138.
[15]
Lakouari N, Oubram O, Bassam A, et al. Modeling and simulation of CO2 emissions in roundabout intersection[J]. Journal of Computational Science, 2020,40:101072.
[16]
Quaassdorff C, Borge R, Pérez J, et al. Microscale traffic simulation and emission estimation in a heavily trafficked roundabout in Madrid (Spain)[J]. Science of the Total Environment, 2016,566:416-427.
[17]
Woodward H, Stettler M, Pavlidis D, et al. A large eddy simulation of the dispersion of traffic emissions by moving vehicles at an intersection[J]. Atmospheric environment, 2019,215:116891.
[18]
Li Z, Xu J, Ming T, et al. Numerical simulation on the effect of vehicle movement on pollutant dispersion in urban street[J]. Procedia Engineering, 2017,205:2303-2310.
[19]
Hang J, Luo Z, Wang X, et al. The influence of street layouts and viaduct settings on daily carbon monoxide exposure and intake fraction in idealized urban canyons[J]. Environmental Pollution, 2017,220:72-86.
[20]
Shih T H, Liou W W, Shabbir A, et al. A new k-eddy viscosity model for high reynolds number turbulent flows[J]. Computers & Fluids, 1995,24(3):227-238.
[21]
Hefny M M, Ooka R. CFD analysis of pollutant dispersion around buildings:Effect of cell geometry[J]. Building and Environment, 2009,44(8):1699-1706.
[22]
Ming T, Davies P, Liu W, et al. Removal of non-CO2 greenhouse gases by large-scale atmospheric solar photocatalysis[J]. Progress in Energy and Combustion Science, 2017,60:68-96.
[23]
Ning Z, Cheung C S, Lu Y, et al. Experimental and numerical study of the dispersion of motor vehicle pollutants under idle condition[J]. Atmospheric Environment, 2005,39(40):7880-7893.
[24]
Shi T, Ming T, Wu Y, et al. The effect of exhaust emissions from a group of moving vehicles on pollutant dispersion in the street canyons[J]. Building and Environment, 2020,181:107120.
[25]
Ming T, Han H, Zhao Z, et al. Field synergy analysis of pollutant dispersion in street canyons and its optimization by adding wind catchers[J]. Building Simulation, 2021,14(2):391-405.
[26]
Ming T, Shi T, Han H, et al. Assessment of pollutant dispersion in urban street canyons based on field synergy theory[J]. Atmospheric Pollution Research, 2021,12(2):341-356.
[27]
Kastner-Klein P, Fedorovich E, Rotach M W. A wind tunnel study of organised and turbulent air motions in urban street canyons[J]. Journal of wind engineering and industrial aerodynamics, 2001,89(9):849- 861.
[28]
刘呈威,赵福云,刘润哲,等.内陆城市热岛与湖风环流耦合特性研究[J]. 中国环境科学, 2019,39(5):1890-1898. Liu C W, Zhao F Y, Liu R Z, et al. Research on multiple circulations co-driven by lake breeze and urban heat islands in inner cities[J]. China Environmental Science, 2019,39(5):1890-1898.
[29]
Saneinejad S, Moonen P, Defraeye T, et al. Coupled CFD, radiation and porous media transport model for evaluating evaporative cooling in an urban environment[J]. Journal of Wind Engineering and Industrial Aerodynamics, 2012,104:455-463.
[30]
Jin M, Zuo W, Chen Q. Simulating natural ventilation in and around buildings by fast fluid dynamics[J]. Numerical Heat Transfer, Part A:Applications, 2013,64(4):273-289.
