Fire Science and Engineering (한국화재소방학회논문지)

Korean Institute of Fire Science and Engineering (한국화재소방학회)
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Numerical Analysis of Unsteady Heat Transfer for the Location Selection of Anti-freeze for the Fire Protection Piping with Electrical Heat Trace

소방 배관 동파방지용 열선의 위치 선정을 위한 비정상 열전달 수치해석

  • Choi, Myoung-Young (Fire Insurers Laboratories of Korea) ;
  • Lee, Dong-Wook (Dept. of Mechanical & Automotive Engineering, Seoul National Univ. of Science & Technology) ;
  • Choi, Hyoung-Gwon (Dept. of Mechanical & Automotive Engineering, Seoul National Univ. of Science & Technology)
  • 최명영 (한국화재보험협회 방재시험연구원) ;
  • 이동욱 (서울과학기술대학교 기계자동차공학과) ;
  • 최형권 (서울과학기술대학교 기계자동차공학과)
  • Received : 2014.01.08
  • Accepted : 2014.02.24
  • Published : 2014.02.28
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Abstract

In this paper, the unsteady incompressible Navier-Stokes equations coupled with energy equation were solved to find out the optimal location of electrical heat trace for anti-freeze of water inside the pipe for fire protection. Since the conduction equation of pipe was coupled with the natural convection of water, the analysis of conjugate heat transfer was conducted. A commercial code (ANSYS-FLUENT) based on SIMPLE-type algorithm was used for investigating the unsteady flows and temperature distributions in water region. From the numerical experiments, the isotherms and the vector fields in water region were obtained. Furthermore, it was found that the lowest part of the pipe cross-section was an optimal position of electrical heat trace assuming the constant thermal expansion coefficient of water since the minimum temperature of the water with the position is higher than those with the other positions.

본 논문에서는 에너지방정식과 비정상 비압축성 Navier-Stokes 방적식을 사용하여 동절기 소방배관의 동파방지를 위한 최적의 열선위치를 확인하였다. 물의 자연대류와 소방 배관의 전도 열방정식이 결합된 복합열전달을 해석하였다. 혼합 열전달 배관 내 물의 비정상적인 유동과 온도분포를 확인하기 위하여 SIMPLE 형태의 알고리즘을 기반으로 한 상용코드(ANSYS-FLUENT)가 사용되었다. 수치해석을 수행하여 등온선과 벡터장을 살펴보았다. 물의 열팽창계수를 일정하다고 가정할 때 소방 배관 단면의 하부에 열선을 설치하는 것이 다른 위치에 설치하는 것보다 시간에 따른 물의 최저온도가 가장 높아서 동파방지에 가장 효과적인 것을 확인할 수 있었다.

Keywords

References

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