• Title/Summary/Keyword: 대배기구

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A study on the operation characteristics of oversized exhaust port applicable to double-deck tunnel (복층터널에 적용 가능한 화재 연동형 대배기구 운영 특성 분석 연구)

  • Park, Jinouk;Yoo, Yongho;Kim, Yangkyun;Park, Byoungjik;Kim, Whiseong
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.21 no.6
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    • pp.887-895
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    • 2019
  • Recently, the number of underground road development projects has been increasing to solve traffic problems in the national capital region and metropolitan areas with intensified overcrowding, and there has been a tendency to plan underground roads by applying a double-deck tunnel technology that has advantages in constructability and economical efficiency. The double-deck tunnel has a structure where one excavation section is divided into two parts and used as up and down lines, and is mainly used as a road for small vehicles only due to its low floor height. In addition, due to the small cross-sectional area, it has characteristics different from those of general road tunnels in terms of ventilation and disaster prevention. In this regard, this study proposed an operational plan that applies an oversized exhaust system, which is one of semi-transverse ventilation systems, to small cross-sectional tunnels like double-deck tunnel with low floor height, and a comparative analysis between smoke exhaust characteristics according to the fire occurrence locations and oversized exhaust systems was conducted using the Fire Dynamics Simulator (FDS). The results showed that unlike uniform exhaust, intensive smoke exhaust using the oversized exhaust port maximized the delay effect of smoke diffusion and limited the smoke within 50 m above and below the fire point.

A study on the fire characteristics according to the installation type of large smoke exhaust port in a small cross sectional tunnel fire (소단면 대심도 터널 화재시 대배기구의 설치형태에 따른 화재특성 연구)

  • Choi, Pan-Gyu;Baek, Doo-San;Yoo, Ji-Oh;Kim, Chang-Yong
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.21 no.1
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    • pp.201-210
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    • 2019
  • Recently, due to the efforts to mitigate traffic congestion and expansion of space efficiency, the construction of underground roads has been increased in big-scale cities. Since tunnels in the city have a higher chance for a fire leading to a great tragedy during a severe traffic jam than mountain tunnels, it is highly likely that it will be constructed as a tunnel, having a small cross section, for small vehicles. However, if they are constructed as such small-vehicle tunnels, it would be possible to reduce the design fire intensity while the concentration of harmful gases would increase due to a reduction in the small cross sectional area, led by a decrease in the tunnel height. In this study, behaviors of fire smoke by the installation interval and format of large-scale exhaust-gas ports were examined and compared in the analysis of temperatures and CO concentrations of a tunnel and its results were as the following. Although there were no significant differences in the smoke spreading distance between installation intervals, but in this study, 100 m was found to be the most effective installation interval. The smoke exhaustion performance was found to be excellent in the order of $4m{\times}3m$, $6m{\times}2m$, and $3m{\times}2m$ (2 lane) of the smoke spreading distance. Although there was no significant difference in the smoke spreading distance between formats of large-scale exhaust-gas ports, it was found that the smoke spreading distance was larger than other cases when it was $3m{\times}2m$ in the fire growing process. The analysis of smoke spreading distances by the aspect ratio showed that a smoke spreading distance was shorted when its the smoke spreading distance was found to be shorter when its traverse distance was relatively longer than its longitudinal distance.

A Study on Setting Smoke Exhaust Rate According to the Transverse Ventilation with Oversized Exhaust Ports in Road Tunnel by the Variation of Fire Intensity (화재강도변화에 따른 횡류식 대배기구 배연량 설정에 관한 연구)

  • Rie, Dong-Ho;Kim, Ha-Young
    • Fire Science and Engineering
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    • v.22 no.2
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    • pp.38-43
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    • 2008
  • Recently, the application of transverse ventilation system in accordance with oversized exhaust ports has been increased in bidirectional road tunnel in order to improving smoke exhaust ability. In this study, numerical simulations were carried out by using FDS (ver. 4.0) which includes variations of exhaust flow rates and heat release rate of fire to obtain the optimal smoke exhaust rate in case of fire in the transversely ventilation system. As a result, smoke exhaust amount tends to increase when the inner velocity is existing in the tunnel. In case of internal longitudinal air velocity 2.5m/s face to the fire, smoke moving distance should be restricted within 250m when the smoke exhaust rate which exceeds $244.8m^3/s$.

A Numerical Study on Characteristics of Smoke Exhaust in Road Tunnel Fires for Different Ventilation System (터널 화재 시 환기 방식에 따른 배연 특성의 수치해석 연구)

  • Kim, Jong-Yoon;Yoo, Ji-Oh
    • Fire Science and Engineering
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    • v.22 no.3
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    • pp.201-207
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    • 2008
  • In this study, three Dimensional CFD simulations were carried out to investigate the effective smoke extraction system in bi-directional road tunnel fires using FLUENT. Characteristics of transverse system with big size extraction port or with uniform extraction port, semi-transverse system and longitudinal system for smoke extraction system were analyzed. Air velocity, port size, and operating method were used with variable. Distributions of smoke spread, CO was analyzed. As a result, the transverse ventilation system with big size port was found to be more effective than the uniform ports for bi-directional road tunnel.

A Study on the Effective Fire and Smoke Control in Road-Tunnel with Semi-Transverse Ventilation (도로터널 화재시 대배기구 환기방식에서의 배연 연구)

  • Jeon, Yong-Han;Han, Sang-Cheol;Yoo, Oh-Ji;Kim, Nam-Jin;Seo, Tae-Boem;Kim, Jong-Yoon
    • Proceedings of the SAREK Conference
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    • pp.1244-1250
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    • 2009
  • In this study it is intended to review the moving characteristics of smoke by performing visualization for the calculation of the optimal smoke exhaust air volume in case a fire occurs in tunnels where transverse ventilation is applied, and to obtain basic data necessary for the design of smoke exhaust systems by deriving optimal smoke exhaust operational conditions under various conditions. As a result of this study, when the critical velocity in the tunnel is 1.75 m/s and 2.5 m/s, the optimal smoke exhaust air volume has to be more than $173\;m^3/s$, $236\;m^3/s$ for the distance of the smoke moving which can limit the distance to 250m. In addition, in case of uniform exhaust the generated smoke is effectively taken away if the two exhaust holes near the fire region are opened at the same time.

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A Study of Smoke Exhaust Rate for the Transverse Ventilation with Oversized Exhaust Ports in Road Tunnel (횡류식 대배기구 방식을 적용한 도로터널에서 화재시 최적배연풍량 선정에 관한 연구)

  • Yoo, Ji-Oh;Yoon, Sung-Wook;Rie, Dong-Ho
    • Journal of the Korean Society of Safety
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    • v.21 no.4
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    • pp.7-12
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    • 2006
  • Recently, the application of transverse ventilation system with oversized exhaust ports has been increased in bidirectional road tunnel in order to improve smoke exhaust ability. Therefore, in this study, for decision of the optimal smoke exhaust rates in the transverse ventilation system, several standards of nations are compared and numerical simulations with variations of exhaust flow rates are carried out in terms of smoke spread distance by FDS ver. 3.1. As results, in the case of no internal longitudinal air velocity in tunnel, the smoke exhaust rate of $80m^{3}/s$ (the smoke generation rate at HRR of 20MW) is sufficient enough to limit the smoke spread within 250m in 6 minutes after the fire. However, in the case of the internal longitudinal air velocity at 2.5m/s, the smoke exhaust rate should be increased $130m^{3}/s$.

An analytical study on the fire characteristics of the small tunnel with large smoke exhaust port (대배기구 배연방식을 적용한 소형차 전용 터널의 화재특성에 관한 해석적 연구)

  • Yoo, Ji-Oh;Kim, Jin-Su;Rhee, Kwan-Seok
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.19 no.3
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    • pp.375-388
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    • 2017
  • In order to solve the traffic congest and environmental issues, small-cross section tunnel for small car only is increasing, but there is not standard for installation of disaster prevention facility. In this study, in order to investigate the behavioral characteristics of thermal environment and smoke in a small cross section tunnels with a large port exhaust ventilation system, the A86, the U-Smartway and the Seobu moterawy tunnel, Temperature and CO concentration in case of fire according to cross sectional area, heat release rate and exhaust air flow rate were analyzed by numerical analysis and the results were as follows. As the cross-sectional area of the tunnel decreases, the temperature of the fire zone increases and the rate of temperature rise is not significantly affected by heat release rate. However, there is a difference depending on the change of the exhaust air flow rate. In the case of applying the exhaust air flow rate $Q_3+2.5Ar$ of the large port exhaust ventilation system, the temperature of the fire zone was 7.1 times for A86 ($Ar=25.3m^2$) and 5.4 time for U-smartway ($Ar=37.32m^2$) by Seobu moterway tunnel ($Ar=46.67m^2$). The CO concentration of fire zone also showed the same tendency. The A86 tunnels were 10.7 times and the U-Smartways were 9.5 times more than the Seobu moterway. Therefore, in the case of a small section tunnel, the thermal environment and noxious gas concentration due to the reduction of the cross-sectional area are expected to increase significantly more than the cross-sectional reduction rate.

Numerical Study on the Improvement Heat and Smoke Control System in Old Subway Station on Train Fire (수치해석을 통한 노후 지하철 역사 내 열차 화재 시 제연모드 개선에 관한 연구)

  • Kim, Hyo-Gyu;Baek, Doo-San;Yoo, Yong-Ho
    • Fire Science and Engineering
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    • v.31 no.3
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    • pp.88-96
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    • 2017
  • The subway can transport a lot of people at a certain route at once, and the railway and the platform are underground, so it is advantageous to use the ground space efficiently. But If a fire occurs in a subway that is used by an unspecified number of people, such as the Daegu Subway Fire Disaster, many casualties can occur. As a result of the previous research, it was confirmed that the performance of the ventilation system of the old subway platform was remarkably degraded. Therefore, in this study, based on the experimental results of the previous research, we confirmed the flow of the hot and CO flows according to the ventilation mode in the case of fire by three - dimensional numerical analysis. As a result, it was found that the old ventilation system could not maintain the hot air temperature below the reference value for 4 minutes based on the evacuation time of the platform, and when the ventilation performance was enhanced by adding Oversized Exhaust Ports at the upper part of the platform, And the temperature of the heat flow can be maintained.

A Study on the Effective Fire and Smoke Control in Road-Tunnel with Semi-Transverse Ventilation (Oversized Exhaust System) (도로터널 화재시 반횡류식 환기방식에서의 최적배연 연구(대배기구 방식))

  • Kim, Jong-Yoon;Jeon, Yong-Han
    • Fire Science and Engineering
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    • v.23 no.3
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    • pp.79-84
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    • 2009
  • The smoke control system plays the most important role in securing evacuation environment when a fire occurs in road tunnels. Smoke control methods in road tunnels are classified into two categories which are longitudinal ventilation system and transverse ventilation system. In this study it is intended to review the characteristics of smoke behavior by performing numerical analysis for calculating the optimal smoke exhaust air volume when a fire occurs in tunnels in which transverse ventilation is applied, and for obtaining the basic data required for the design of smoke exhaust systems by deriving optimal smoke exhaust operational conditions for various conditions. As a result of this study, when the critical velocity in the tunnel is 1.75m/s and 2.5m/s, the optimal smoke exhaust air volume has to be more than $173m^3/s$, $236m^3/s$ for the distance of the smoke moving which can limit the distance to 250m. In addition, in case of uniform exhaust the generated smoke is effectively taken away if the two exhaust holes near the fire region are opened at the same time.

A study on the effective fire and smoke control in transverse oversized exhaust ventilation (횡류식 선택대배기환기에서의 배연특성에 관한 연구)

  • Han, Sang-Pil;Jeon, Yong-Han
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.13 no.6
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    • pp.451-462
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    • 2011
  • The smoke control system plays the most important role in securing evacuation environment when a fire occurs in road tunnels. Smoke control methods in road tunnels are classified into two categories which are longitudinal ventilation system and transverse ventilation system. In this study it is intended to review the characteristics of smoke behavior by performing numerical analysis for calculating the optimal smoke exhaust air volume with scaled-model and simulation when a fire occurs in tunnels in which transverse ventilation is applied, and for obtaining the basic data required for the design of smoke exhaust systems by deriving optimal smoke exhaust operational conditions for various conditions. As a result of this study, when the critical velocity in the tunnel is 1.75 m/s and 2.5 m/s, the optimal smoke exhaust air volume has to be more than $173m^3/s$, $236m^3/s$ for the distance of the smoke moving which can limit the distance to 250 m. In addition, in case of uniform exhaust the generated smoke is effectively taken away if the two exhaust holes near the fire region are opened at the same time.