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He, K., Li, Y. Z., Ingason, H., Shi, L. & Cheng, X. (2024). Experimental study on the maximum ceiling gas temperature driven by double fires in a tunnel with natural ventilation. Tunnelling and Underground Space Technology, 144, Article ID 105550.
Åpne denne publikasjonen i ny fane eller vindu >>Experimental study on the maximum ceiling gas temperature driven by double fires in a tunnel with natural ventilation
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2024 (engelsk)Inngår i: Tunnelling and Underground Space Technology, ISSN 0886-7798, E-ISSN 1878-4364, Vol. 144, artikkel-id 105550Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

The maximum gas temperature below the ceiling is an important parameter for tunnel safety. The present study analyzed the characteristics of the maximum excess ceiling gas temperature driven by double fire sources in a naturally ventilated tunnel. A series of small-scale tunnel fire experiments were carried out with different fire separation distances and heat release rates. Theoretical analysis based on the equivalent virtual origin was also performed. The results showed that there exists only one peak gas temperature when the two fire plumes are merged before reaching the ceiling, while two peak gas temperatures can be observed when the two fire plumes are completely separated. The maximum excess gas temperature below the tunnel ceiling gradually decreases with an increasing fire separation distance in the plume merging region (S < Scp). When the fire separation distance increases further (S > Scp), the effect of the fire separation distance on the maximum gas temperature below the ceiling is very limited. Furthermore, a model using an equivalent fire source was proposed to predict the maximum excess gas temperature below the ceiling, considering different plume merging states. The present study contributes to the understanding of the maximum excess gas temperature characteristics of the smoke flow driven by double fires with an equal heat release rate in naturally ventilated tunnels. 

sted, utgiver, år, opplag, sider
Elsevier Ltd, 2024
Emneord
Ceilings; Fires; Gases; Merging; Smoke; Thermal plumes; Ventilation; Double fire source; Fire separation; Gas temperature; Heat release; Maximum excess gas temperature; Natural ventilation; Separation distances; Temperature profiles; Tunnel fires; Ventilated tunnels; Gas temperature
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-68815 (URN)10.1016/j.tust.2023.105550 (DOI)2-s2.0-85180417123 (Scopus ID)
Forskningsfinansiär
Brandforsk
Merknad

This work was financially supported by National Key Research and Development Program of China (No. 2022YFC3005201 ), the Tunnel and Underground Safety Center (TUSC), the Swedish Fire Research Board (BRANDFORSK), Youth Innovation Promotion Association CAS (No. CX2320007001 ), Fundamental Research Funds for the Central Universities under Grants (No. WK2320000048 and No. WK2320000056 ) and USTC Tang Scholar, which are greatly acknowledged.

Tilgjengelig fra: 2024-01-08 Laget: 2024-01-08 Sist oppdatert: 2024-01-08bibliografisk kontrollert
Li, Y. Z., Ingason, H., Blom, J., Arvidson, M. & Försth, M. (2024). Mechanisms and performance of different fixed fire fighting systems in tunnels – summary of laboratory and tunnel fire tests.
Åpne denne publikasjonen i ny fane eller vindu >>Mechanisms and performance of different fixed fire fighting systems in tunnels – summary of laboratory and tunnel fire tests
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2024 (engelsk)Rapport (Annet vitenskapelig)
Abstract [en]

This report presents both small scale laboratory tests and tunnel fire tests carried out in a FORMAS project. Four series of small scale laboratory tests were conducted to obtain the material properties, burning properties, water spray distributions, and spray droplet size distributions. The main efforts were, by adopting the Froude scaling, seven series of tests conducted in a about 50 m long container tunnel with a scale of 1 to 3. This report presents results on the influence of low pressure, medium pressure and high pressure water-based fixed fire fighting systems (FFFSs) on fire development, fire spread to adjacent vehicles, structural protection, tenability, smoke control, spray deflection and spray resistances. The focus is to compare the performance of three default FFFSs and to evaluate the efficiency of each of the FFFS. The results show that the default low pressure FFFS performs well in term of suppressing the fire development, preventing the fire spread to nearby vehicles, providing tenable conditions for evacuation and rescue service, protecting tunnel structure and easing the problem with spray deflection due to tunnel ventilation. The default high pressure FFFS is usually on the opposite side while the default medium pressure FFFS usually lie in between.

Publisher
s. 75
Serie
RISE Rapport ; 2024:22
Emneord
tunnel fire, fixed fire fighting system, fire suppression, fire spread, ventilation, smoke control, deflection, ventilation resistance, structural protection
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-72327 (URN)978-91-89896-70-3 (ISBN)
Forskningsfinansiär
Swedish Research Council Formas
Tilgjengelig fra: 2024-03-15 Laget: 2024-03-15 Sist oppdatert: 2024-04-05bibliografisk kontrollert
Li, Y. Z., Svensson, R., Wahlqvist, J., Van Hees, P. & Ingason, H. (2024). Numerical modelling of water sprays and fire suppression in tunnels.
Åpne denne publikasjonen i ny fane eller vindu >>Numerical modelling of water sprays and fire suppression in tunnels
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2024 (engelsk)Rapport (Annet vitenskapelig)
Abstract [en]

This work aims to validate numerical modelling of water sprays against experiments carried out in this project. The focus has been on the influence of ventilation on water distributions on the tunnel floor, the influence of water sprays on control of smoke flow, and the modelling of pool fires and crib fires. Besides, full scale tunnel fires with FFFS in tunnels using longitudinal ventilation and point extraction ventilation systems are simulated and compared, as well recommendations for numerical modelling of such scenarios.

Publisher
s. 117
Serie
RISE Rapport ; 2024:23
Emneord
tunnel fire, water spray, FFFS, smoke control, water distribution, pyrolysis modelling, ventilation
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-72328 (URN)978-91-89896-71-0 (ISBN)
Forskningsfinansiär
Swedish Research Council Formas, 2019-00521
Merknad

The work is a part of the project “Mechanisms and performance of different fixed fire fighting systems (FFFS) in tunnels” funded by Swedish Research Council FORMAS (2019-00521), which is gratefully acknowledged.

Tilgjengelig fra: 2024-03-15 Laget: 2024-03-15 Sist oppdatert: 2024-04-05bibliografisk kontrollert
Willstrand, O., Pushp, M., Ingason, H. & Brandell, D. (2024). Uncertainties in the use of oxygen consumption calorimetry for heat release measurements in lithium-ion battery fires. Fire safety journal, 143, Article ID 104078.
Åpne denne publikasjonen i ny fane eller vindu >>Uncertainties in the use of oxygen consumption calorimetry for heat release measurements in lithium-ion battery fires
2024 (engelsk)Inngår i: Fire safety journal, ISSN 0379-7112, E-ISSN 1873-7226, Vol. 143, artikkel-id 104078Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

Accurate measurement of the heat release from a battery fire is vital for risk management, product development and construction of accurate models. Oxygen consumption calorimetry is the most common method for heat release measurements in experimental fire tests. The strength of the method is that it can be applied to unknown compositions of fuel with sufficient accuracy. Despite that this method is used to estimate heat release from battery fires, the method is subject to discussion. In this work, the method is studied in-depth, and potential errors are structured and quantified. Uncertainties associated with self-generated oxygen and internal heat generation, total gas release from the battery and impact on the heat release calculations, as well as the assumed E-factor (i.e., heat release per unit mass of oxygen consumed), are thoroughly discussed. For a Li-ion battery fire, it is concluded that oxygen consumption calorimetry will exclude internal heat generation and underestimate the total heat released from the external flaming fire by up to 10 %. In addition, high rate of combustion reactions can result in that the measured peak heat release rate is underestimated much more, up to 100 %. 

sted, utgiver, år, opplag, sider
Elsevier Ltd, 2024
Emneord
Calorimeters; Calorimetry; Carbon dioxide; Enthalpy; Fires; Heat generation; Ions; Lithium compounds; Oxygen; Risk assessment; Risk management; Uncertainty analysis; Carbon dioxide generation calorimetries; Fire tests; Heat release; Heat release rate; Oxygen consumption calorimetry; Release measurements; Release rate; Thermal runaways; Total heat released; Uncertainty; Lithium-ion batteries
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-70010 (URN)10.1016/j.firesaf.2023.104078 (DOI)2-s2.0-85181765133 (Scopus ID)
Forskningsfinansiär
Vinnova, 2019-00064Swedish Energy Agency, 51787-1
Merknad

This work is part of a project funded by the Swedish Energy Agency (project no. 51787-1). Partners within the project comprise of RISE Research Institutes of Sweden, Northvolt, Scania, and Uppsala University. We also acknowledge support from Batteries Sweden (grant no. Vinnova-2019-00064), and STandUP for Energy.

Tilgjengelig fra: 2024-01-16 Laget: 2024-01-16 Sist oppdatert: 2024-01-16bibliografisk kontrollert
Ingason, H. (2023). Branddynamik i oventilerade väg- och järnvägstunnlar.
Åpne denne publikasjonen i ny fane eller vindu >>Branddynamik i oventilerade väg- och järnvägstunnlar
2023 (svensk)Rapport (Annet vitenskapelig)
Abstract [en]

This report describes the fire dynamic conditions in natural ventilated tunnels. A summary of the today’s knowledge about the dynamic fire conditions in nonventilated road or railway tunnel is given. The concept of fire dynamic conditions includes the variation of different parameters in length and height at different ventilation conditions. This primarily applies to parameters such as fire development, heat and smoke gas dispersion, gas temperatures, heat radiation towards objects and surrounding wall construction, flame lengths and sight length and toxic conditions in the smoke gases.

Publisher
s. 61
Serie
RISE Rapport ; 2023:113
Emneord
tunnel, slope, natural ventilation, fire, stratification, gas temperature, gas velocity, radiation, gas concentrations.
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-67745 (URN)978-91-89821-98-9 (ISBN)
Merknad

Uppdraget är initierat av Trafikverket och är ett uppdrag inom ramen för Tunnel and Underground Safety Center (TUSC).

Tilgjengelig fra: 2023-11-13 Laget: 2023-11-13 Sist oppdatert: 2023-11-13bibliografisk kontrollert
Jiang, L., Olofsson, A., Ingason, H., Evegren, F. & Mindykowski, P. (2023). Effect of opening geometries on fire development in a ro-ro space. Ships and Offshore Structures, 272-284
Åpne denne publikasjonen i ny fane eller vindu >>Effect of opening geometries on fire development in a ro-ro space
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2023 (engelsk)Inngår i: Ships and Offshore Structures, ISSN 1744-5302, E-ISSN 1754-212X, s. 272-284Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

A series of model scale experiments were conducted to study the fire development in a ro-ro deck with various opening geometries. The experiments were performed in a 1/8 reduced scale model with a heptane pool fire as fire source. Experimental results show that both the ventilation factor and the opening position affect the fire development. The critical opening ratio for the fire to self-extinguish is 4%, with the opening locating at the bottom of the side walls while no self-extinction is found for other tests. A higher opening position and a larger opening height provide better flow exchange between the deck and the ambient, but this effect is only obvious for 4% opening. Numerical study shows that Fire Dynamic Simulator used with default simple settings underestimates the fire development and yields an early extinction when fire self-extinction occurs. For freely developed fire with large openings, FDS gives more close results to experiments.

Emneord
Ro-ro space; fire development; opening; ventilation
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-58834 (URN)10.1080/17445302.2022.2038467 (DOI)
Forskningsfinansiär
Swedish Transport AdministrationThe Swedish Mercantile Marine Foundation
Merknad

The tests and simulations constitute parts of the research project RO5 (ro-ro spacefire ventilation) which isfinanced by Swedish Transport Administration (Trafikverket) and The Swedish Mercantile Marine Foundation (Stiftelsen Sveriges Sjömanshus).

Tilgjengelig fra: 2022-03-18 Laget: 2022-03-18 Sist oppdatert: 2023-11-02bibliografisk kontrollert
He, K., Li, Y. Z., Ingason, H. & Cheng, X. (2023). Fire spread among multiple vehicles in tunnels using longitudinal ventilation. Tunnelling and Underground Space Technology, 133, Article ID 104967.
Åpne denne publikasjonen i ny fane eller vindu >>Fire spread among multiple vehicles in tunnels using longitudinal ventilation
2023 (engelsk)Inngår i: Tunnelling and Underground Space Technology, ISSN 0886-7798, E-ISSN 1878-4364, Vol. 133, artikkel-id 104967Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

The characteristics of fire spread among multiple vehicles in tunnels using longitudinal ventilation were investigated by analyzing the experimental data from a series of fire tests in a 1:15 scale tunnel. Further, a simple theoretical model for gas temperature in a tunnel with multiple fire sources was proposed and used in analysis of the experimental data. The results showed that, for objects (wood piles) placed at a same separating distance downstream of the fire, the fire spread occurred faster and faster along the tunnel. Validation of the simplified temperature model for multiple fire sources was made against both model and full-scale tunnel fire tests. The model was further used to predict the critical conditions for fire spread to the second and third objects. Comparisons with the test data showed that average excess temperature of 465 K (or an equivalent incident heat flux of 18.7 kW/m2) could be used as the criterion for fire spread, and this was verified further by other model-scale tests and full-scale tests. The results showed that the critical fire spread distance monotonously increases with the heat release rate, and decreases with the tunnel perimeter. For multiple fire sources with equivalent heat release rates, as the separation distance between the first two fire sources increases, the critical fire spread distance from the second fire source to the third fire source decreases, but the total fire spread distance from the first fire source to the third one increases. If the total heat release rate at the site of a downstream fire source is greater than that at the former fire source, the critical fire spread distance becomes longer.

sted, utgiver, år, opplag, sider
Elsevier, 2023
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-64962 (URN)10.1016/j.tust.2022.104967 (DOI)
Merknad

This project was financially supported by the Tunnel and Underground Safety Center (TUSC), and the Swedish Fire Research Board (BRANDFORSK), which are greatly acknowledged. 

Highlights:•Fire spread in tunnels using longitudinal ventilation was studied.•A simplified temperature model for tunnel with multiple fire sources was proposed.•Criterion for fire spread to two nearby vehicles in tunnel was investigated.•Critical fire spread distance in a tunnel with multiple fire sources was discussed.

 

 

Tilgjengelig fra: 2023-06-09 Laget: 2023-06-09 Sist oppdatert: 2023-06-12bibliografisk kontrollert
Guo, Q., Li, Y. Z., Ingason, H., Yan, Z. & Zhu, H. (2023). Numerical study on thermally driven smoke flow characteristics in long tunnels under natural ventilation. International journal of thermal sciences, 192, Article ID 108379.
Åpne denne publikasjonen i ny fane eller vindu >>Numerical study on thermally driven smoke flow characteristics in long tunnels under natural ventilation
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2023 (engelsk)Inngår i: International journal of thermal sciences, ISSN 1290-0729, E-ISSN 1778-4166, Vol. 192, artikkel-id 108379Artikkel i tidsskrift (Fagfellevurdert) 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

sted, utgiver, år, opplag, sider
Elsevier Masson s.r.l., 2023
Emneord
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
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-64422 (URN)10.1016/j.ijthermalsci.2023.108379 (DOI)2-s2.0-85154579409 (Scopus ID)
Merknad

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.

Tilgjengelig fra: 2023-05-11 Laget: 2023-05-11 Sist oppdatert: 2023-06-08bibliografisk kontrollert
Li, Y. Z., Lönnermark, A., Gehandler, J. & Ingason, H. (Eds.). (2023). Proceedings from the Tenth International Symposium on Tunnel Safety and Security. Paper presented at Tenth International Symposium on Tunnel Safety and Security. STAVANGER, NORWAY, APRIL 26-28, 2023.
Åpne denne publikasjonen i ny fane eller vindu >>Proceedings from the Tenth International Symposium on Tunnel Safety and Security
2023 (engelsk)Konferanseproceedings (Fagfellevurdert)
Abstract [en]

This publication includes the Proceedings of the 10th International Symposium on Tunnel Safety and Security (ISTSS) held in Stavanger, Norway, April 26-28, 2023. The Proceedings include 45 papers and 16 posters. The papers were presented in 16 different sessions, i.e., Keynote sessions, Alternative Fuel Vehicle Safety, Risk Management & Explosion, Digitization, Explosion, Poster Corner, Ventilation 1&2, Fixed Fire Fighting Systems, Tenability and Evacuation, Emergency Management, Evacuation, Safety Management, Fire Dynamics and Resistance. Each day was opened by invited Keynote Speakers (in total five) addressing broad topics of pressing interest. The Keynote Speakers, selected as leaders in their field, consisted of Ove Njå (University of Stavanger, Norway), Vladimir Molkov (Ulster University, UK), Ulf Lundström (Swedish Transport Administration, Sweden), Mirjam Nelisse (TNO, The Netherlands), and Gunnar Jenssen (SINTEF, Norway). We are grateful that the keynote speakers were able to share their knowledge and expertise with the participants of the symposium.

Publisher
s. 680
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-67532 (URN)978-91-89757-89-9 (ISBN)
Konferanse
Tenth International Symposium on Tunnel Safety and Security. STAVANGER, NORWAY, APRIL 26-28, 2023
Tilgjengelig fra: 2023-10-16 Laget: 2023-10-16 Sist oppdatert: 2023-11-29bibliografisk kontrollert
Zhao, S., Yang, H., Li, Y. Z., Ingason, H. & Liu, F. (2023). Theoretical and numerical study on smoke descent during tunnel fires under natural ventilation condition. Tunnelling and Underground Space Technology, 142, Article ID 105414.
Åpne denne publikasjonen i ny fane eller vindu >>Theoretical and numerical study on smoke descent during tunnel fires under natural ventilation condition
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2023 (engelsk)Inngår i: Tunnelling and Underground Space Technology, ISSN 0886-7798, E-ISSN 1878-4364, Vol. 142, artikkel-id 105414Artikkel i tidsskrift (Fagfellevurdert) Published
Abstract [en]

The smoke stratification and the smoke descent along a tunnel are of the utmost importance for personnel evacuation. The paper investigates the smoke descent along a tunnel during a naturally ventilated tunnel fire. A theoretical model is developed to predict the smoke depth below the ceiling along the tunnel. A series of numerical simulations of full-scale tunnel fires are conducted to compare with the developed model, and some coefficients such as the entrainment coefficient are determined from the simulation results. The concepts of critical moment and critical distance are proposed to characterize the smoke descent along the tunnel. The results show that as the smoke spreads longitudinally, the smoke depth below the tunnel ceiling continuously increases. The temperature decay along the tunnel due to heat losses and air entrainment at the smoke layer interface is considered as the main parameter for the smoke descent. After the vitiated air returns back to the fire source, the smoke stratification in the entire tunnel will be significantly reduced. The smoke layer depth along the tunnel based on the temperature distribution is relatively stable in the process of smoke development, which is not sensitive to the HRR, but influenced by the tunnel width, and this method could only be used before the critical moment. The outcomes of this study could provide references for a better understanding of smoke movement in naturally ventilated tunnels and provide technical guidelines for fire safety designers.

sted, utgiver, år, opplag, sider
Elsevier Ltd, 2023
Emneord
Air entrainment; Fires; Ventilation; Condition; Critical moment; Natural ventilation; Personnel evacuations; Smoke descent; Smoke layer; Smoke stratification; Stratification; Tunnel fires; Ventilated tunnels; Smoke
HSV kategori
Identifikatorer
urn:nbn:se:ri:diva-67456 (URN)10.1016/j.tust.2023.105414 (DOI)2-s2.0-85171775524 (Scopus ID)
Merknad

The authors would like to acknowledge the Tunnel and Underground Safety Center (TUSC) for the financial support. Thanks to Qinghua Guo for the valuable discussions and technical assistance during his stay at RISE. Shengzhong Zhao and Haoran Yang were also financially supported by the National Natural Science Foundation of China (No. 52208115 ), the Natural Science Foundation of Shandong Province (No. ZR2020QE279 ) and Plan of Guidance and Cultivation for Young Innovative Talents of Shandong Province.

Tilgjengelig fra: 2023-10-06 Laget: 2023-10-06 Sist oppdatert: 2023-10-06bibliografisk kontrollert
Organisasjoner
Identifikatorer
ORCID-id: ORCID iD iconorcid.org/0000-0002-9340-6768
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