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Numerical simulation on the influence of viaduct gradient and vehicle-induced effect on pollutant dispersion and exposure risk

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高架斜坡及车辆诱导效应对污染物传播与暴露风险研究

Journal Information

J. Hefei Univ. Tech. (Nat. Sci.), Dec.2024, Vol.47 No.12: 1595-1600

DOI: 10.3969/j.issn.1003-5060.2024.12.002

Authors

YU Xin, LIU Xiaoping, ZHANG Guangwei, ZHU Jian

(School of Civil and Hydraulic Engineering, Hefei University of Technology, Hefei 230009, China)

Abstract and Keywords

Abstract: Taking the urban street canyon with viaduct gradient as the research object, using numerical simulation technology, and selecting carbon monoxide(CO) as a typical representative of vehicle exhaust, the intake fraction and personal intake fraction were adopted to evaluate the CO exposure risk of pedestrians and nearby residents. The comprehensive influence of viaduct gradient and vehicle-induced effect on airflow and pollutant dispersion was explored. In addition, the effects of aspect ratio of the street canyon and differences in emissions of vehicles on viaduct gradient were taken into account. The results showed that the presence of viaduct gradient in the street canyon hindered the diffusion of pollutants, and the maximum dimensionless concentration ( $ K_{c} $) at the higher positions on both sides of the viaduct gradient could reach more than six times that at the lower positions. It had a great impact on the residents of high-rise buildings around the viaduct. Vehicle movement resulted in building surface concentrations above the viaduct deck that were 1-2 orders of magnitude higher than those without vehicle movement, showing the influence of vehicle-inducing effect. When the aspect ratio (H/W) was 3, the concentration on the windward side of the street canyon was significantly higher than that in other cases, and the concentration difference was 1-2 orders of magnitude. The greater the aspect ratio, the more unfavorable the diffusion of pollutants.

Keywords: viaduct gradient; street canyon; vehicle-induced effect; pollutant; intake fraction

作者信息

俞欣，刘晓平，张光伟，祝健

（合肥工业大学土木与水利工程学院，安徽合肥230009）

摘要和关键词

摘要: 文章以带有坡度路面高架的城市街谷为研究对象，基于数值模拟技术，选用CO作为车辆尾气的典型代表物，采用吸入分数和个人吸入分数评估道路附近居民和行人的CO暴露风险，探究高架斜坡和车辆诱导效应对气流组织和污染物扩散的综合影响，并考虑街谷高宽比和车辆在斜坡行驶时排放差异影响。结果表明，街谷内带有坡度高架路面对污染物扩散及分布有显著影响，高架斜坡两侧较高位置处的最大无量纲质量浓度 $ K_{c} $值可达到较低位置处的6倍以上，对于该类高架周边高层建筑用户产生较大影响。在引入车辆运动效应下，同类场景高架桥面上方的建筑物表面质量浓度显著高出1～2个数量级，表明车辆诱导效应不容忽视。街谷高宽比H/W为3时的迎风面质量浓度显著高于其他情况下的质量浓度，质量浓度相差1～2个数量级，高宽比越大越不利于污染物的扩散。

关键词: 高架斜坡；街道峡谷；车辆诱导效应；污染物；吸入分数

Funding

国家重点研发计划资助项目（2018YFC0810600）

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