Coupling effect of vehicle wake and jet flow on the dispersion characteristics and dilution efficiency of pollutants in urban highway tunnels

Shanshan Zhao; Jingchao Xie; Peng Xue; Yining Wang; Zhenxiong Jiang; Jiaping Liu

doi:10.1016/j.scitotenv.2023.164926

Coupling effect of vehicle wake and jet flow on the dispersion characteristics and dilution efficiency of pollutants in urban highway tunnels

Sci Total Environ. 2023 Oct 1:893:164926. doi: 10.1016/j.scitotenv.2023.164926. Epub 2023 Jun 15.

Authors

Shanshan Zhao¹, Jingchao Xie², Peng Xue³, Yining Wang⁴, Zhenxiong Jiang⁵, Jiaping Liu⁶

Affiliations

¹ Beijing Key Laboratory of Green Building Environment and Energy Saving Technology, Beijing University of Technology, Beijing 100124, China; Faculty of Architecture, Civil and Transportation Engineering, Beijing University of Technology, Beijing 100124, China. Electronic address: zhao191015@emails.bjut.edu.cn.
² Beijing Key Laboratory of Green Building Environment and Energy Saving Technology, Beijing University of Technology, Beijing 100124, China; Faculty of Architecture, Civil and Transportation Engineering, Beijing University of Technology, Beijing 100124, China. Electronic address: xiejc@bjut.edu.cn.
³ Beijing Key Laboratory of Green Building Environment and Energy Saving Technology, Beijing University of Technology, Beijing 100124, China; Faculty of Architecture, Civil and Transportation Engineering, Beijing University of Technology, Beijing 100124, China. Electronic address: xp@bjut.edu.cn.
⁴ Beijing Key Laboratory of Green Building Environment and Energy Saving Technology, Beijing University of Technology, Beijing 100124, China; Faculty of Architecture, Civil and Transportation Engineering, Beijing University of Technology, Beijing 100124, China. Electronic address: wyn@emails.bjut.edu.cn.
⁵ Jiangsu Provincial Transport Engineering Construction Bureau, Nanjing 210004, China.
⁶ Beijing Key Laboratory of Green Building Environment and Energy Saving Technology, Beijing University of Technology, Beijing 100124, China; Faculty of Architecture, Civil and Transportation Engineering, Beijing University of Technology, Beijing 100124, China; State Key Laboratory of Green Building in Western China, Xi'an University of Architecture and Technology, Xi'an 710055, China. Electronic address: liujiaping@bjut.edu.cn.

PMID: 37327896
DOI: 10.1016/j.scitotenv.2023.164926

Abstract

The pollutants emitted by traveling vehicles are prone to accumulation inside urban highway tunnels, which poses a serious threat to the driving safety and health of passengers. This study employed the dynamic mesh method to simulate a traveling vehicle and investigated the coupling effect of vehicle wake and jet flow on the dispersion characteristics of pollutants in urban highway tunnels. To ensure the accuracy of the numerical simulation results, the turbulence model (realizable k-ε model) and dynamic mesh model were validated through field tests. The results revealed that jet flow can disrupt the large-scale longitudinal vortices pattern in the wake region, whereas vehicle wake can simultaneously weaken the entrainment strength of jet flow. The jet flow was found to be decisive in the space with a height greater than 4 m, whereas the vehicle wake intensity was considerably stronger at the bottom space of the tunnel, leading to the accumulation of pollutants in the passenger breathing zone. To evaluate the effect of jet fans on pollutants in the breathing zone, an innovative dilution efficiency was proposed. The dilution efficiency can be significantly affected by the intensity of vehicle wake and turbulence. Moreover, the dilution efficiency of alternative jet fans was better than that of traditional jet fans.

Keywords: Breathing zone; Dilution efficiency; Dynamic mesh method; Flow characteristics; Pollutant dispersion.