Numerical study on thermally driven smoke flow characteristics in long tunnels under natural ventilationShow others and affiliations
2023 (English)In: International journal of thermal sciences, ISSN 1290-0729, E-ISSN 1778-4166, Vol. 192, article id 108379Article in journal (Refereed) Published
Abstract [en]
The paper focuses on the flow structures and mass flow rates of thermally driven smoke flows induced by fires in long transportation tunnels under natural ventilation. The important influencing factors including heat release rate (HRR), tunnel width and height, are taken into consideration. The mechanism of the smoke flow movement is explored. The results show that for a fire in a long naturally ventilated transportation tunnel, there exists a critical point which is dependent on HRR and tunnel geometry. This critical point is defined as the location where the smoke layer thickness and the outgoing mass flow rate increase towards it and decrease after it. Further, it is found that the critical point moves farther away from the fire source in a wider or higher tunnel, while it lies closer to the fire source for a higher HRR. A correlation is proposed to estimate the location of the critical point. The outgoing mass flow rates along the tunnel are calculated using the two-layer flow model and well-mixed flow model of thermally driven flows, and the results indicate that these models produce satisfactory predictions of the mass flow rates if the vertical temperature profile is known. © 2023 The Authors
Place, publisher, year, edition, pages
Elsevier Masson s.r.l. , 2023. Vol. 192, article id 108379
Keywords [en]
Critical point, Long tunnel, Mass flow rate, Smoke flow structure, Tunnel fire, Flow rate, Flow structure, Mass transfer, Smoke, Ventilation, Heat release, Long tunnels, Mass-flow rate, Natural ventilation, Release rate, Smoke flows, Thermally driven, Tunnel fires, Fires
National Category
Engineering and Technology
Identifiers
URN: urn:nbn:se:ri:diva-64422DOI: 10.1016/j.ijthermalsci.2023.108379Scopus ID: 2-s2.0-85154579409OAI: oai:DiVA.org:ri-64422DiVA, id: diva2:1756399
Note
Correspondence Address: Y.Z. Li; Fire and Safety, RISE Research Institutes of Sweden, Borås, Box 857, SE-501 15, Sweden; email: yingzhen.li@ri.se; The author(s) would like to acknowledge the Tunnel and Underground Safety Center (TUSC) for the financial support. This work was also financially supported by National Natural Science Foundation of China ( 52208408 ), Key Laboratory of Large Structure Health Monitoring and Control in Hebei Province ( KLLSHMC2101 ) and Taiyuan University of Science and Technology ( 20232014 ) in China.
2023-05-112023-05-112023-06-08Bibliographically approved