A numerical study on effects of thermal buoyance force on number of jet fans for smoke control

Ji-Oh* Yoo; Hyun-Jun Shin

doi:10.9711/KTAJ.2013.15.3.301

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2013 Vol.15, Issue 3 Preview Page Next Page

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

31 May 2013. pp. 301-310

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Abstract

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.

Keywords

Thermal buoyance force

Jet fans

Tunnel fire

현재 도로터널에는 화재시 임계풍속을 유지할 수 있도록 제트팬을 설치하고 있으며, 제트팬 댓수는 임계풍속을 유지하기 위한 유동저항, 자연풍에 의한 환기저항, 열부력에 의한 환기저항을 고려하여 산정한다. 그러나, 국내의 경우, 제트팬 댓수 산정시 열부력은 고려하지 않고 있는 실정이다. 이에 본 연구에서는 열부력이 제트팬 댓수에 미치는 영향을 검토하기 위해서 터널연장(500, 750, 1000, 1500, 2000, 3500 m) 및 경사도(-1.0, -1.5, -2.0%)를 변수로 하여 화재성장곡선에 따른 비정상상태의 수치 시뮬레이션을 수행하였으며, 열기류의 평균온도 및 열부력에 의한 압력손실을 검토하여 열부력이 제트팬 댓수에 미치는 영향을 검토하였다. 이에 본 연구에서는 화재로 인한 열부력을 고려하는 경우에 제트팬 댓수의 증가가 필요하며, 특히, 설계화재강도를 100 MW로 하는 경우에는 본 해석조건의 모든 범위에서 열부력에 의한 압력손실이 차량저항에 의한 압력손실의 최대치보다 증가하며, 현행설계기준을 적용하는 경우보다. 최소 2～11대의 제트팬 대수의 증가가 필요한 것으로 분석되었다. 따라서 제연용 제트팬 용량 산정시 열부력에 대한 고려가 반드시 필요한 것으로 나타났다.

키워드

열부력

제연용 제트팬

도로터널 화재

References

MLIT, Design and Management for Road Tunnel Fire Protection , Seoul. MLIT. (2009)

Korea Expressway Corporation, The investigation of the performance of smoke exhaust system in JukRyung Tunnel , Seoul. Bumchang Eng.. (2004)

NEMA, National Fire Safety Code for Road Tunnel(NFSC 603) , Seoul. NEMA. (2012)

The Norwegian Road and Transport Department, Road Tunnels(Handbooks) (2010)

Federal Department of Environment, Transport, Energy and Communications, Luftung der Strassentunnel- Systemwahl , ASTRA 13001. Dimensionierung und Ausstattung. (2008)

Austrian Research Association for Roads, Rail and Transport (FSV), Guidelines and Regulations for Road Construction (RVS 09.02.31) (2008)

CETU (Centre D’etudes des Tunnels), Inter- ministry circular n°2000-63 of 25 August 2000 relating to the safety of tunnels in the national highways network(Appendix n°2) (2000)

harvey N and Fuster T, ISAVVT 13rd, USA, BHR Group, “Design fire heat release rate selection – impacts for road tunnels” , 1; 211-223 (2009)

FGSV (Forschungs Gesellschaft fuer Strassen- und Verkehrswesen) workgroup of traffic management and road safety, RABT Guidelines for the Equipment and Operation of Road Tunnels (2006)

J.O. Yoo, B.C. Oh and H.G. Kim, J. of Korean tunnel under-ground Sp Assoc., “A numerical study on the characteristics of the smoke movement and the effects of the structure in road tunnel fire.” , 15(3); 289-300 (2013)

Information

Publisher :Korean Tunneling and Underground Space Association
Publisher(Ko) :한국터널지하공간학회
Journal Title :Journal of Korean Tunnelling and Underground Space Association
Journal Title(Ko) :한국터널지하공간학회 논문집
Volume : 15
No :3
Pages :301-310
Received Date : 2013-04-29
Revised Date : 2013-05-14
Accepted Date : 2013-05-21
DOI :https://doi.org/10.9711/KTAJ.2013.15.3.301

Journal of Korean Tunnelling and Underground Space Association ISSN:2233-8292(Print) 2287-4747(Online) 한국터널지하공간학회 논문집

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