Environmental Impact of Discharge Patterns and Ambient Wind on the Jet Discharge from a Mechanical Upper Vent of a Tunnel

Flow characteristics and pollutant dispersion characteristics of a mechanical upper vent of a tunnel under various discharge patterns and ambient wind were studied by using the computational fluid dynamics (CFD) numerical method and an experimental model. On this basis, variations in the environment...

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Autores principales:	Xin Zhang, Ke Wu, Kai Zhu
Formato:	article
Lenguaje:	EN
Publicado:	MDPI AG 2021
Materias:	urban tunnel mechanical upper vent environmental impact radius computational fluid dynamics (CFD) ambient wind Technology T Engineering (General). Civil engineering (General) TA1-2040 Biology (General) QH301-705.5 Physics QC1-999 Chemistry QD1-999
Acceso en línea:	https://doaj.org/article/fedd197b99f442f197e4b238096491eb
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spelling	oai:doaj.org-article:fedd197b99f442f197e4b238096491eb2021-11-11T14:59:17ZEnvironmental Impact of Discharge Patterns and Ambient Wind on the Jet Discharge from a Mechanical Upper Vent of a Tunnel10.3390/app112198582076-3417https://doaj.org/article/fedd197b99f442f197e4b238096491eb2021-10-01T00:00:00Zhttps://www.mdpi.com/2076-3417/11/21/9858https://doaj.org/toc/2076-3417Flow characteristics and pollutant dispersion characteristics of a mechanical upper vent of a tunnel under various discharge patterns and ambient wind were studied by using the computational fluid dynamics (CFD) numerical method and an experimental model. On this basis, variations in the environmental impact radius <i>r</i><sub>criti</sub> changing with the ambient wind velocity <i>U</i> for pollutants from vertical and horizontal outlets were also analyzed with the set discharge capacity. According to our findings, the pollutant emission of the upper vent under a vertical discharge pattern can be considered as free buoyant jet diffusion under the impact of the momentum of ambient wind, while the emission under the horizontal discharge pattern can be regarded as semi-confined buoyant jet diffusion under the impact of the momentum of ambient wind. Moreover, the <i>r</i><sub>criti</sub> of the vertical outlet increased with the increase of <i>U</i> when <i>U</i> ≤ 3 m/s and was minimally affected by <i>U</i> for <i>U</i> > 3 m/s. Additionally, the <i>r</i><sub>criti</sub> of the horizontal outlet decreased with the increase of <i>U</i>. When the discharge capacity was constant, the <i>r</i><sub>criti</sub> of the upper vent under both vertical and horizontal discharge patterns declined with the increase of the discharge velocity <i>V</i><sub>0</sub>. Note that the <i>r</i><sub>criti</sub> of the vertical outlet was smaller than that of the horizontal one for the range of parameters considered. These results can provide a theoretical reference for optimizing the design of a vent on the top of an urban tunnel.Xin ZhangKe WuKai ZhuMDPI AGarticleurban tunnelmechanical upper ventenvironmental impact radiuscomputational fluid dynamics (CFD)ambient windTechnologyTEngineering (General). Civil engineering (General)TA1-2040Biology (General)QH301-705.5PhysicsQC1-999ChemistryQD1-999ENApplied Sciences, Vol 11, Iss 9858, p 9858 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	urban tunnel mechanical upper vent environmental impact radius computational fluid dynamics (CFD) ambient wind Technology T Engineering (General). Civil engineering (General) TA1-2040 Biology (General) QH301-705.5 Physics QC1-999 Chemistry QD1-999
spellingShingle	urban tunnel mechanical upper vent environmental impact radius computational fluid dynamics (CFD) ambient wind Technology T Engineering (General). Civil engineering (General) TA1-2040 Biology (General) QH301-705.5 Physics QC1-999 Chemistry QD1-999 Xin Zhang Ke Wu Kai Zhu Environmental Impact of Discharge Patterns and Ambient Wind on the Jet Discharge from a Mechanical Upper Vent of a Tunnel
description	Flow characteristics and pollutant dispersion characteristics of a mechanical upper vent of a tunnel under various discharge patterns and ambient wind were studied by using the computational fluid dynamics (CFD) numerical method and an experimental model. On this basis, variations in the environmental impact radius <i>r</i><sub>criti</sub> changing with the ambient wind velocity <i>U</i> for pollutants from vertical and horizontal outlets were also analyzed with the set discharge capacity. According to our findings, the pollutant emission of the upper vent under a vertical discharge pattern can be considered as free buoyant jet diffusion under the impact of the momentum of ambient wind, while the emission under the horizontal discharge pattern can be regarded as semi-confined buoyant jet diffusion under the impact of the momentum of ambient wind. Moreover, the <i>r</i><sub>criti</sub> of the vertical outlet increased with the increase of <i>U</i> when <i>U</i> ≤ 3 m/s and was minimally affected by <i>U</i> for <i>U</i> > 3 m/s. Additionally, the <i>r</i><sub>criti</sub> of the horizontal outlet decreased with the increase of <i>U</i>. When the discharge capacity was constant, the <i>r</i><sub>criti</sub> of the upper vent under both vertical and horizontal discharge patterns declined with the increase of the discharge velocity <i>V</i><sub>0</sub>. Note that the <i>r</i><sub>criti</sub> of the vertical outlet was smaller than that of the horizontal one for the range of parameters considered. These results can provide a theoretical reference for optimizing the design of a vent on the top of an urban tunnel.
format	article
author	Xin Zhang Ke Wu Kai Zhu
author_facet	Xin Zhang Ke Wu Kai Zhu
author_sort	Xin Zhang
title	Environmental Impact of Discharge Patterns and Ambient Wind on the Jet Discharge from a Mechanical Upper Vent of a Tunnel
title_short	Environmental Impact of Discharge Patterns and Ambient Wind on the Jet Discharge from a Mechanical Upper Vent of a Tunnel
title_full	Environmental Impact of Discharge Patterns and Ambient Wind on the Jet Discharge from a Mechanical Upper Vent of a Tunnel
title_fullStr	Environmental Impact of Discharge Patterns and Ambient Wind on the Jet Discharge from a Mechanical Upper Vent of a Tunnel
title_full_unstemmed	Environmental Impact of Discharge Patterns and Ambient Wind on the Jet Discharge from a Mechanical Upper Vent of a Tunnel
title_sort	environmental impact of discharge patterns and ambient wind on the jet discharge from a mechanical upper vent of a tunnel
publisher	MDPI AG
publishDate	2021
url	https://doaj.org/article/fedd197b99f442f197e4b238096491eb
work_keys_str_mv	AT xinzhang environmentalimpactofdischargepatternsandambientwindonthejetdischargefromamechanicalupperventofatunnel AT kewu environmentalimpactofdischargepatternsandambientwindonthejetdischargefromamechanicalupperventofatunnel AT kaizhu environmentalimpactofdischargepatternsandambientwindonthejetdischargefromamechanicalupperventofatunnel
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Environmental Impact of Discharge Patterns and Ambient Wind on the Jet Discharge from a Mechanical Upper Vent of a Tunnel

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