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2010 Vol.12, Issue 3 Preview Page
Variation of time-dependent convection heat transfer coefficients in heat transfer analysis at various initial heating rates of tunnel fire scenarios

요소제거모델을 활용한 열전달해석에서 터널 화재이력곡선의 초기가열구배에 따른 대류열전달계수의 변화

Soon-Wook Choi1
,
Soo-Ho* Chang2*
,
Jun-Hwan Lee3
,
Sung-Yul Ahn4
최 순욱1
,
장 수호*2*
,
이 준환3
,
안 성율4
1한국건설기술연구원 기반시설연구본부 지반연구실 연구원, 연세대학교 사회환경시스템공학부 대학원
2한국건설기술연구원 기반시설연구본부 지반연구실 연구위원
3연세대학교 사회환경시스템공학부 부교수
4사이텍이앤씨 대표이사
*교신저자. *Corresponding Author. 
31 May 2010. pp. 223-237
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Abstract

The initial heating rate is well known as one of the most influencing factors on the occurrence of spalling and the loss of strength in concrete after fire initiation. In this study, a series of fire tests were carried out at different initial heating rates to find out its effects on the deterioration of tunnel structural members. Heat transfer analyses combined with an element elimination model were also carried out to verify its applicability in the same conditions as the fire tests. Moreover, the convection heat transfer coefficients compatible with fire test results were derived from parametric studies. In this course, their time-dependent variations were also analyzed at different initial heating rates. Finally, a numerical formula to estimate the heat transfer coefficients at the various initial heating rates was proposed by the interpolation of the results of numerical analyses.

Keywords
Tunnel
fire
heating rate
convection coefficient
element elimination model

본 연구에서는 화재에 의한 콘크리트의 단면손실과 역학적 특성을 저하하는 주요 요인 가운데 온도증가율, 즉 초기가열구배를 변화시키면서 모의화재실험을 수행하였다. 그리고 수행된 모의화재실험에서 관찰된 단면손실을 모사하기 위하여 요소제거모델을 활용한 유한요소해석법에 의해 열전달해석을 수행하였다. 이때 모의화재실험결과와 수치해석결과가 가장 일치하는 대류열전달계수를 반복적인 해석과정을 통해 도출하였다. 이상의 과정으로부터 얻어진 초기가열구배에 따른 대류열전달계수의 변화를 조사한 결과, 각 초기가열구배별 대류열전달계수의 변화는 분수함수 형태로 근사시킬 수 있었다. 최종적으로 모의화재실험으로부터 도출된 초기가열구배별 대류열전달계수의 변화 결과를 내삽하여 다양한 초기가열구배에 따른 화재경과시간별 대류열전달계수의 변화를 추정할 수 있는 수식을 함께 제시하였다.

키워드
터널
화재
초기가열구배
대류열전단계수
요소제거모델
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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 : 12
  • No :3
  • Pages :223-237
  • Received Date : 2010-02-22
  • Revised Date : 2010-04-06
  • Accepted Date : 2010-04-26
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