• Title/Summary/Keyword: Smoke propagation

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Characteristics of Smoke Propagation in Railway Tunnels with Rescue Station (구난역을 갖는 철도 터널 내부의 연기거동 특성)

  • Jang, Won-Cheol;Kim, Dong-Woon;Lee, Seong-Hyuk;Ryou, Hong-Sun
    • Fire Science and Engineering
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    • v.23 no.4
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    • pp.13-18
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    • 2009
  • The main objective of the present study is to investigate smoke propagation in railway tunnels with rescue stations. In particular, based on measurement of HRR (heat release rate) for pool fires formed at different locations, the influence of fire source location on smoke behavior is examined. The fuel is n-heptane and pool fires are generated with a square length 4cm. With the use of MVHS (Modified Volumetric Heat Source) model for fire source, extensive numerical simulations are performed by using the commercial code FLUENT (Ver.6.3) Predicted smoke temperatures and smoke propagation are discussed. From numerical predictions, it is found that ventilation systems may be necessary in the railway tunnels because the smoke moves along the tunnel, and consequently it enters the non-accident tunnel. It is also confirmed that the cross-passage and fire protection wall systems contribute to control the smoke.

Numerical Simulation on the Heat and Smoke Flow Phenomena Due to the Fire in a Cyclodrome (경륜장 내부의 화재발생에 따른 열 및 연기 거동에 대한 수치적 연구)

  • 박원희;김태국;손봉세
    • Fire Science and Engineering
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    • v.17 no.3
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    • pp.13-19
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    • 2003
  • In this paper, numerical calculations are conducted to predict the characteristics of the heat transfer and smoke propagation in a cydodrome. The gas flow velocity and temperature around the origin of the fire is obtained by using a plume model and the turbulent flow characteristics are considered by standard $textsc{k}$-$\varepsilon$ turbulent model. In this study, the transient thermal behavior can be used for designing fire detection of large rooms.

The dynamic characteristics of upper hot gas layer and smoke propagation along with tunnel slope in case of fire (터널 내 화재 시 경사에 따른 온도층 및 연기유동 특성)

  • Rie, Dong-Ho;Kim, Ha-Young;Moon, Sung-Woong;Yoo, Ji-Oh
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.11 no.3
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    • pp.223-228
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    • 2009
  • The aim of this research is to analyse the dynamic characteristics of the hot upper smoke layer in case of fire in a tunnel. In order to get the result, computer simulation technique has been used. The fire scenarios were set on the basis of standard cross section of national and express highways through NIST's FDS. As the area of a tunnel increased, the influence of the wind velocity decreased. Furthermore, the influence of the slope of a road was reduced as the wind velocity increased. On the other hand, as the wind velocity increased, the influence of the slope of a road decreased. This phenomena is believed to be caused by the cooling effect of wind which is over 1 m/s in speed, hence, reducing the influence of the effect of slope.

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An Experimental Study on Smoke Spread Using a Reduced-scale Subway Building Model (지하역사 축소모델을 이용한 연기확산에 대한 실험적 연구)

  • Kim, Myung-Bae;Choi, Byung-Il
    • Fire Science and Engineering
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    • v.22 no.2
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    • pp.49-56
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    • 2008
  • Smoke propagation for the Daegu Metro fire is reproduced by a reduced-scale model experiment. The three-story station building was modeled with 1/20-scale, and the tunnel connected to the platform was not completely modeled because of its length. To include the flow resistance the tunnel provides the mesh screens were used in the model. The fire scenario was selected based on the fire growth rate of the metro car seat where the fire initiated. The time when smoke arrived at each compartment in the station building was measured by thermocouples and visualization. Regarding fire ventilation, the air supply that has been accepted as conventional design in a subway metro building intensifies smoke spread. The results show that the whole building was filled with smoke in about 10 minutes in case of no ventilation.

A Study on Ventilation Effects on Smoke Behavior in Rescue Station for Tunnel Fires (철도터널 화재시 구난역 내의 연기거동에 미치는 배연효과에 관한 연구)

  • Jang, Won-Cheol;Kim, Dong-Woon;Lee, Seong-Hyuk;Ryou, Hong-Sun
    • Journal of the Korean Society for Railway
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    • v.11 no.3
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    • pp.294-299
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    • 2008
  • The present study investigates the ventilation effects on smoke spreading with the rescue stations. Experiments for tunnel fires were carried out for n-heptane pool em at different fire locations, and the heat release rates (HRR) were obtained by addition, using the commercial code (FLUENT), the present article presents numerical results for smoke behavior in railway tunnels with rescue station, and it uses the MVHS (Modified Volumetric Heat Source) model for estimation of combustion products resulting from the fire source determined from the HRR measurement. As a result, it is found that smoke propagation is prevented successfully by the fire doors located inside the cross-passages and especially, the smoke behavior in the accident tunnel can be controlled through the ventilation system because of substantial change in smoke flow direction in the cross-passages.

Ventilation Effects on Smoke Behavior in Rescue Station for Tunnel Fires (철도터널 화재시 구난역 내의 연기거동에 미치는 배연효과에 관한 수치연구)

  • Jang, Won-Cheol;Kim, Dong-Woon;Ryou, Hong-Sun;Lee, Seong-Hyuk
    • Proceedings of the KSR Conference
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    • 2008.06a
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    • pp.2130-2138
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    • 2008
  • The present study investigates the ventilation effects on smoke spreading characteristics in railway tunnels with the rescue stations. Experiments were carried out for n-heptane pool fires with a square length 4 cm at different fire locations, and the heat release rates (HRR) were obtained by the measurement of burning rates. In addition, using the commercial code (FLUENT), the present article presents numerical results for smoke behavior in railway tunnels with rescue station, and it uses the MVHS (Modified Volumetric Heat Source) model for estimation of combustion products resulting from the fire source determined from the HRR measurement. As a result, it is found that smoke propagation is prevented successfully by the fire doors located inside the cross-passages and especially, the smoke behavior in the accident tunnel can be controlled through the ventilation system because of substantial change in smoke flow direction in the cross-passages.

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A study on the effect of air velocity through a damper on smoke extraction performance in case of fire in road tunnels (도로터널 화재 시 집중배기방식의 배기포트 통과풍속이 배연성능에 미치는 영향에 관한 연구)

  • Ryu, Ji-Oh;Na, Kwang-Hoon
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.22 no.4
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    • pp.347-365
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    • 2020
  • In order to resolve traffic problems in urban areas and to increase the area of green spaces, tunnels in downtown areas are being increased. Additionally, the application of large port smoke extraction ventilation systems is increasing as a countermeasure to smoke extraction ventilation for tunnels with high potential for traffic congestion. It is known that the smoke extraction performance of the large port smoke extraction system is influenced not only by the amount of the extraction flow rate, but also by various factors such as the shape of the extraction port (damper) and the extraction air velocity through a damper. Therefore, in this study, the design standards and installation status of each country were investigated. When the extraction air flow rate was the same, the smoke extraction performance according to the size of the damper was numerically simulated in terms of smoke propagation distance, compared and evaluated, and the following results were obtained. As the cross-sectional area of the smoke damper increases, the extraction flow rate is concentrated in the damper close to the extraction fan, and the smoke extraction rate of the damper in downstream decreases, thereby increasing the smoke propagation distance on the downstream side. In order to prevent such a phenomenon, it is necessary to reduce the cross-sectional area of the smoke damper and increase the velocity of passing air through the damper so that the pressure loss passing through the damper increases, thereby reducing the non-uniformity of smoke extraction flow rate in the extraction section. In this analysis, it was found that when the interval distance of the extraction damper was 50 m, the air velocity passing through damper was 4.4 m/s or more, and when the interval distance of the extraction dampers was 100 m, the air velocity passing through damper was greater than 4.84 m/s, it was found to be advantageous to ensure smoke extraction performance.

The Risk Assessment of Tunnel Fire Through Real Scale Fire Test (실물터널 화재실험을 통한 터널화재 위험도 평가)

  • 최준석;최병일;김명배;한용식;장용재;이유환;황낙순;김필영
    • Fire Science and Engineering
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    • v.16 no.3
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    • pp.71-76
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    • 2002
  • The real scale tunnel fire tests are carried out for the first time in domestic range to assess the extent of risk in the tunnel fire. The tunnel dimension is 465 m in length, 9.2 m in width and 6.5 m in height. Gasoline pools with 0.25 MW∼2.5 MW size and a 1500CC passenger car are used as fire sources. Six jet fans are used to change the flow velocity inside the tunnel. Temperatures at total 86 points in the tunnel are measured to find the temperature distribution and smoke behavior in the real tunnel fire. In the experiment, it is examined that the important parameters to assess the extent of risk in tunnel fire such as back layering of smoke front, descending of smoke layer and the fire size of a real passenger car.

Computer modelling of fire consequences on road critical infrastructure - tunnels

  • Pribyl, Pavel;Pribyl, Ondrej;Michek, Jan
    • Structural Monitoring and Maintenance
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    • v.5 no.3
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    • pp.363-377
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    • 2018
  • The proper functioning of critical points on transport infrastructure is decisive for the entire network. Tunnels and bridges certainly belong to the critical points of the surface transport network, both road and rail. Risk management should be a holistic and dynamic process throughout the entire life cycle. However, the level of risk is usually determined only during the design stage mainly due to the fact that it is a time-consuming and costly process. This paper presents a simplified quantitative risk analysis method that can be used any time during the decades of a tunnel's lifetime and can estimate the changing risks on a continuous basis and thus uncover hidden safety threats. The presented method is a decision support system for tunnel managers designed to preserve or even increase tunnel safety. The CAPITA method is a deterministic scenario-oriented risk analysis approach for assessment of mortality risks in road tunnels in case of the most dangerous situation - a fire. It is implemented through an advanced risk analysis CAPITA SW. Both, the method as well as the resulting software were developed by the authors' team. Unlike existing analyzes requiring specialized microsimulation tools for traffic flow, smoke propagation and evacuation modeling, the CAPITA contains comprehensive database with the results of thousands of simulations performed in advance for various combinations of variables. This approach significantly simplifies the overall complexity and thus enhances the usability of the resulting risk analysis. Additionally, it provides the decision makers with holistic view by providing not only on the expected risk but also on the risk's sensitivity to different variables. This allows the tunnel manager or another decision maker to estimate the primary change of risk whenever traffic conditions in the tunnel change and to see the dependencies to particular input variables.