Numerical Study on Smoke Characteristics in Ultra-Long Tunnels with Multi-Train Fire Scenarios
Metropolitan city express line tunnels are fully enclosed and often span long distances between stations, allowing multiple trains within a single interval. Traditional segmented ventilation ensures only one train per section, but ultra-long tunnels with shaftless designs introduce new challenges un...
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| Format: | Article |
| Language: | English |
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MDPI AG
2025-07-01
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| Series: | Fire |
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| Online Access: | https://www.mdpi.com/2571-6255/8/7/265 |
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| _version_ | 1839616010230956032 |
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| author | Jiaming Zhao Cheng Zhang Saiya Feng Shiyi Chen Guanhong He Yanlong Li Zhisheng Xu Wenbin Wei |
| author_facet | Jiaming Zhao Cheng Zhang Saiya Feng Shiyi Chen Guanhong He Yanlong Li Zhisheng Xu Wenbin Wei |
| author_sort | Jiaming Zhao |
| collection | DOAJ |
| description | Metropolitan city express line tunnels are fully enclosed and often span long distances between stations, allowing multiple trains within a single interval. Traditional segmented ventilation ensures only one train per section, but ultra-long tunnels with shaftless designs introduce new challenges under fire conditions. This study investigates smoke behavior in an ultra-long inter-district tunnel during multi-train blockage scenarios. A numerical model evaluates the effects of train spacing, fire source location, and receding spacing on smoke back-layering, temperature distribution, and flow velocity. Results indicate that when train spacing exceeds 200 m and longitudinal wind speed is above 1.2 m/s, the impact of train spacing on smoke back-layering becomes negligible. Larger train spacing increases back-layering under constant wind speed, while higher wind speeds reduce it. Fire source location and evacuation spacing affect the extent and pattern of smoke spread and high-temperature zones, especially under reverse ventilation conditions. These findings provide quantitative insights into fire-induced smoke dynamics in ultra-long tunnels, offering theoretical support for optimizing ventilation control and evacuation strategies in urban express systems. |
| format | Article |
| id | doaj-art-0ce7244c444c44baae2ae6cdaf8c7b8b |
| institution | Matheson Library |
| issn | 2571-6255 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Fire |
| spelling | doaj-art-0ce7244c444c44baae2ae6cdaf8c7b8b2025-07-25T13:22:46ZengMDPI AGFire2571-62552025-07-018726510.3390/fire8070265Numerical Study on Smoke Characteristics in Ultra-Long Tunnels with Multi-Train Fire ScenariosJiaming Zhao0Cheng Zhang1Saiya Feng2Shiyi Chen3Guanhong He4Yanlong Li5Zhisheng Xu6Wenbin Wei7China Academy of Building Research Fire Institute, Beijing 100013, ChinaChina Academy of Building Research Fire Institute, Beijing 100013, ChinaSchool of Civil Engineering, Central South University, Changsha 410075, ChinaSchool of Civil Engineering, Central South University, Changsha 410075, ChinaGuangzhou Metro Design & Research Institute Co., Ltd., Guangzhou 510030, ChinaChina Academy of Building Research Fire Institute, Beijing 100013, ChinaSchool of Civil Engineering, Central South University, Changsha 410075, ChinaChina Academy of Building Research Fire Institute, Beijing 100013, ChinaMetropolitan city express line tunnels are fully enclosed and often span long distances between stations, allowing multiple trains within a single interval. Traditional segmented ventilation ensures only one train per section, but ultra-long tunnels with shaftless designs introduce new challenges under fire conditions. This study investigates smoke behavior in an ultra-long inter-district tunnel during multi-train blockage scenarios. A numerical model evaluates the effects of train spacing, fire source location, and receding spacing on smoke back-layering, temperature distribution, and flow velocity. Results indicate that when train spacing exceeds 200 m and longitudinal wind speed is above 1.2 m/s, the impact of train spacing on smoke back-layering becomes negligible. Larger train spacing increases back-layering under constant wind speed, while higher wind speeds reduce it. Fire source location and evacuation spacing affect the extent and pattern of smoke spread and high-temperature zones, especially under reverse ventilation conditions. These findings provide quantitative insights into fire-induced smoke dynamics in ultra-long tunnels, offering theoretical support for optimizing ventilation control and evacuation strategies in urban express systems.https://www.mdpi.com/2571-6255/8/7/265extra-long interval tunnelmultiple trainsfire smoke spreadtemperature distribution |
| spellingShingle | Jiaming Zhao Cheng Zhang Saiya Feng Shiyi Chen Guanhong He Yanlong Li Zhisheng Xu Wenbin Wei Numerical Study on Smoke Characteristics in Ultra-Long Tunnels with Multi-Train Fire Scenarios Fire extra-long interval tunnel multiple trains fire smoke spread temperature distribution |
| title | Numerical Study on Smoke Characteristics in Ultra-Long Tunnels with Multi-Train Fire Scenarios |
| title_full | Numerical Study on Smoke Characteristics in Ultra-Long Tunnels with Multi-Train Fire Scenarios |
| title_fullStr | Numerical Study on Smoke Characteristics in Ultra-Long Tunnels with Multi-Train Fire Scenarios |
| title_full_unstemmed | Numerical Study on Smoke Characteristics in Ultra-Long Tunnels with Multi-Train Fire Scenarios |
| title_short | Numerical Study on Smoke Characteristics in Ultra-Long Tunnels with Multi-Train Fire Scenarios |
| title_sort | numerical study on smoke characteristics in ultra long tunnels with multi train fire scenarios |
| topic | extra-long interval tunnel multiple trains fire smoke spread temperature distribution |
| url | https://www.mdpi.com/2571-6255/8/7/265 |
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