• Title, Summary, Keyword: 제트팬

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A numerical study on effects of thermal buoyance force on number of jet fans for smoke control (도로터널 화재시 열부력이 제연용 제트팬 댓수에 미치는 영향에 대한 해석적 연구)

  • Yoo, Ji-Oh;Shin, Hyun-Jun
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.15 no.3
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    • pp.301-310
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    • 2013
  • Jet fans are installed in road tunnels in order to maintain critical velocity when fire occurs. Generally the number of jet fans against fire are calculated by considering critical velocity and flow resistance by wall friction, vehicle drag force, thermal buoyance force and natural wind. In domestic case, thermal buoyance force is not considered in estimating the number of jet fans. So, in this study, we investigated the pressure loss due to the thermal buoyance force induced by tunnel air temperature rise and the impact of thermal buoyance force on the number of jet fans by the numerical fire simulation for the tunnel length(500, 750, 1000, 1500, 2000, 3500m) and grade (-1.0, -1.5, -2.0%). Considering the thermal buoyance force, number of jet fans have to be increased. Especially in the case of 100MW of heat release rate, the pressure loss due to thermal buoyance force exceed the maximum pressure loss due to vehicle drag resistance, so it is analyzed that number of 2~11 jet fans are needed additionally than current design criteria. Thus, in case of estimating the number of jet fans, it must be considered of thermal buoyance force induced tunnel air temperature rise by fire.

A Study on the Ventilation Performance for Fan flow effect of Model Tunnel(II) (모형도로터널의 환기성능에 미치는 FAN유량에 관한 연구(II))

  • Kim, Se-Jong;Han, Jung-Chul;Lee, Ju-Hee;Kwon, Young-Jin
    • Proceedings of the Korea Institute of Fire Science and Engineering Conference
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    • pp.313-318
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    • 2011
  • 도로터널은 반지하 공간으로서 환기에 많은 설비와 구조에 대한 연구가 진행되고 있으며 특히 제트팬의 경우 평상시에는 환기를 담당하고 있다. 또한 화재시에는 화재연기의 유독가스를 효과적으로 차단하는 제연역할을 함으로서 피난에 대한 중요한 역할을 담당한다. 이러한 제트팬의 특성을 정량적으로 유추하고 공학적인 QRA의 수행을 위한 기초적 연구로서 터널내부의 제트팬의 환기특성을 알아보기 위하여 모형실험체의 내부측정을 2/3까지한 전보에 이어 이번 연구에서는 터널내부전체를 측정하여 제트팬이 모형터널내에 미치는 영향을 CFD와 비교한 연구이다.

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A Study on Smoke Control Characteristic by the Effect off Jet Fan Installation Distance (제트팬 이격거리에 따른 연기제어특성에 관한 연구)

  • Kim, Jong-Yoon;Jeon, Yong-Han;Seo, Tae-Beom;Yoo, Ji-Oh;Rie, Dong-Ho
    • Fire Science and Engineering
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    • v.22 no.1
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    • pp.16-23
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    • 2008
  • In this research, the visualization experiment for a scaling tunnel was conducted to establish the optimum fire protection system in tunnel fires. In order to find the optimal operating condition of jet fan with the fire, the characteristics of smoke propagation was considered to find the optimal operating condition of jet fan at the time of tunnel fire, the concentration of smoke was measured experimentally for various jet fan position and it's operating condition. As a result, when jet fan in the vicinity of fire operates at the upstream, the back-layering of the smoke should be considered with separation distance from the fire source. The distance between the jet fan and the fire should be longer than 50 m. On the other hand, when the vicinity jet fan operates at the downstream, the back-layering of smoke does not occur, but stratification is not maintained because the smoke dispersion occurs at the downstream due to the operation of the jet fan.

Effect of Re-ventilated Fan Capacity on Road Tunnel Fire (제트팬 용량이 도로터널 화재에 미치는 영향)

  • Kim, Kang-Hee;Cho, Mok-Lyang;Kim, Tae-Kwon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.9
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    • pp.204-210
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    • 2019
  • In case of a fire inside a tunnel, unlike ordinary roads, it is very difficult for a driver to obtain visibility, and a large accident is highly likely to occur. In this study, the smoke behavior, visible distance, and CO concentration of a jet fan were analyzed using the NIST fire simulation (FDS). All analyses were set to HRRPUA (Heat Release Rate Per Area) 3.6MW/m and all the analysis times were set to 600s. In all analyses by CFD, the results were confirmed at y=30m and y=110m, and smoke behavior analysis, visible range analysis, and carbon monoxide concentration were confirmed according to the diameter and flow rate. As the size and flow rate of the jet fan increased, the visibility distance was high at y=30m, and the concentration of carbon monoxide was also confirmed to be 0 ppm. Therefore, proper setting of the jet fan diameter and flow rate will be an excellent solution for fires in tunnels, and taking refuge at upstream area of a re-ventilated fan can reduce the number of casualties.

A Study on a Graphical Method for Determining the Characteristics of Jet-fan Ventilation System using the Contour Map of Required Ventilation Rate in Local Highways (지역별 소요환기량 특성도를 활용한 제트팬 환기방식 가능 터널제원 결정연구)

  • 김효규;김화수;김종대;이창우
    • Tunnel and Underground Space
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    • v.13 no.3
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    • pp.235-243
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    • 2003
  • Recent worldwide trends show that tunnel length is getting longer, and the demand for longitudinal ventilation system with jet-fans in highway tunnels has also increased mainly due to the economic reasons. Improvements in vehicle engine subsequently reduced required ventilation rate(Qreq) which is the decisive factor in choosing the optimal ventilation system. Qreq contour map is a graph that defines the relationship among tunnel length, grade and required ventilation rate. It is important to understand the variation of Qreq in order to evaluate the characteristics of ventilation system with jet fans. Therefore this study aims at studying a graphical method for determining the characteristics of jet-fm ventilation system using Qreq contour map. Also, this study focuses on traffic composition on local highways.

An Experimental Study of Smoke Control in Tunnel Fires with Jet Fan (터널화재시 제트팬에 의한 연기제어에 관한 실험적 연구)

  • 이성룡;김충익;유홍선;방기영
    • Tunnel and Underground Space
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    • v.12 no.2
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    • pp.92-98
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    • 2002
  • In this study reduced-scale experiments were conducted to analyze smoke movement in tunnel fire with jet fan, The 1/20 scale experiments were carried out under the froude scaling using gasoline pool fire range from 6.6 to 12.5 cm in diameter with total heat release rate from 0.714 to 4.77 kW. In the case of fires under the 2.5kW, backlaying was reduced about 40cm and smoke was effectively controled in downstream of the fan when operating the fan. The smoke layer was moved down and the ceiling temperature was decreased compared to that of without fan case in upstream of the fan, but the temperature in the lower part of the tunnel was increased.

NUMERICAL ANALYSIS OF TUNNEL FLOW INDUCED BY JET FAN (제트팬 운전에 의해 형성되는 터널내 유동에 대한 수치적 해석)

  • Kim, J.Y.
    • 한국전산유체공학회:학술대회논문집
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    • pp.10-13
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    • 2010
  • The flow field in road tunnel is influenced by some facts such as piston effect of vehicle's move, operation of ventilation facilities, natural wind and buoyancy effect of fire plume. Among those, jet fan is one of main ventilation facilities especially in longitudinal ventilation system of tunnel. In this study to analyze tunnel flow induced by operation of jet fan, numerical simulation has been carried out. The velocity distributions and streamlines in tunnel are examined to consider the three-dimensional characteristics of tunnel flow caused by jet fan.

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A Study on an Optimal Design of Jet Fan Location Considering the Voltage Drops in Tunnels (전압강하를 고려한 터널내 환기 및 방재팬의 경제적 위치선정에 대한 연구)

  • Kim, Eun-Soo;Kim, Hyo-Gyu;Song, Jung-Ho
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • pp.105-109
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    • 2004
  • 우리나라 지형의 특성은 약 70%가 산으로 이루어져 있다. 이러한 지형적 여건은 교통과 관련된 사회간접 자본의 증가로 이어지며, 최근에는 산업의 발전에 힘입어 교통량의 증가와 물류비용의 절감을 목적으로 철도 및 도로의 건설시 터널의 계획 및 시공이 증가되고 있는 추세이다. 이에 따라 터널의 환경개선과 화재시 제연을 목적으로 설치되는 제트팬(Jet Fan)의 용량이 차지하는 전기적 비중이 높아지고, 전압강하에 대한 손실율이 증가되고 있다. 따라서 제트팬의 설치시 배치방법과 터널의 길이에 따른 전기실 배치를 Case 별로 분류하여 전압강하를 계산하고 분석하여 가장 효율적이며 경제적인 방안을 연구하고 정리하여 향후 설계시 기초자료를 제공하고자 하였다.

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A study on the ventilation control method of road tunnel for small vehicles (소형차 전용 도로터널의 환기기 제어방안에 대한 연구)

  • Ryu, Ji-Oh;Lee, Hu-Young;Chang, Ji-Don
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.21 no.6
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    • pp.749-762
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    • 2019
  • In recent years, in urban areas, underground of roads are being promoted in order to resolve traffic congestion and to secure green spaces, and due to the low ratio of large vehicles, they are planned or constructed as road tunnels for small cars only. In addition, the tunnels being built in the city is a tendency to be enlarged to play the role of main roads. Accordingly, the capacity of the ventilation system is increasing and various ventilation methods are required, and the importance of maintenance after the completion of the tunnel such as the operating cost of the ventilation system is emphasized. Therefore, the need for optimization of the operation stage for reducing the power consumption of the ventilation system and the study of the ventilation system operation control logic is increasing. In this study, the study on the necessity of the optimization of operation stage and control logic of the ventilation system was carried out to realize the energy-saving operation for the small car only passing through tunnels which is applied of ① jet fan and combination ventilation system (② jet fan + air purifying equipment, ③ jet fan + vertical shaft, ④ jet fan + supply air semi-transverse). As a result of this study, there can be various operating combinations in the case of the combined ventilation system, and even though the amount of ventilation air is the same, the operating power varies greatly according to the operating combinations. It was found that operating the axial fan first rather than the jet fan first operation method has an effect on power saving.

Experimental study of improvement of ventilation efficiency at intersection in network-form underground road tunnel (네트워크형 지하 도로터널 분기부에서의 환기효율 향상방안에 대한 실험적 연구)

  • Lee, Ho-Seok;Hong, Ki-Hyuk;Choi, Chang-Rim;Kang, Myung-Koo;Lim, Jae-Bom;Mun, Hong-Pyo
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.14 no.2
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    • pp.107-116
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    • 2012
  • The experiment was performed to analyze the intersectional ventilation efficiency by intersection structure and Jet Fan in network-form road tunnel. For this, the size of real road tunnel was reduced by 1/45. To apply traffic inertia force when driving, blower fan was used to form an airflow in model tunnel and the intersectional efficiency was also investigated by measuring the speed at local point of the tunnel. To improve the reduction of ventilation caused by the structure character, Jet Fan was installed to optimize ventilation efficiency in tunnel.