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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MDPI AG
2021-10-01
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| Online Access: | https://www.mdpi.com/2076-3417/11/21/9858 |
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| author | Xin Zhang Ke Wu Kai Zhu |
| author_facet | Xin Zhang Ke Wu Kai Zhu |
| author_sort | Xin Zhang |
| collection | DOAJ |
| 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. |
| first_indexed | 2024-03-10T06:08:05Z |
| format | Article |
| id | doaj.art-fedd197b99f442f197e4b238096491eb |
| institution | Directory Open Access Journal |
| issn | 2076-3417 |
| language | English |
| last_indexed | 2024-03-10T06:08:05Z |
| publishDate | 2021-10-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Applied Sciences |
| spelling | doaj.art-fedd197b99f442f197e4b238096491eb2023-11-22T20:24:11ZengMDPI AGApplied Sciences2076-34172021-10-011121985810.3390/app11219858Environmental Impact of Discharge Patterns and Ambient Wind on the Jet Discharge from a Mechanical Upper Vent of a TunnelXin Zhang0Ke Wu1Kai Zhu2School of Electronic Engineering, Xi’an Shiyou University, Xi’an 710065, ChinaCollege of Civil Engineering and Architecture, Zhejiang University, Hangzhou 310058, ChinaCollege of Quality & Safety Engineering, China Jiliang University, Hangzhou 310018, ChinaFlow 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.https://www.mdpi.com/2076-3417/11/21/9858urban tunnelmechanical upper ventenvironmental impact radiuscomputational fluid dynamics (CFD)ambient wind |
| spellingShingle | 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 Applied Sciences urban tunnel mechanical upper vent environmental impact radius computational fluid dynamics (CFD) ambient wind |
| title | 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_short | 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 |
| topic | urban tunnel mechanical upper vent environmental impact radius computational fluid dynamics (CFD) ambient wind |
| url | https://www.mdpi.com/2076-3417/11/21/9858 |
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