Fire Science and Engineering (한국화재소방학회논문지)

Korean Institute of Fire Science and Engineering (한국화재소방학회)
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Comparison of the Effects of Straight and Twisted Heat Trace Installations Based on Three-dimensional Unsteady Heat Transfer

열선의 직선시공과 감기시공의 동파방지 효과 비교를 위한 3차원 비정상 수치해석

  • Choi, Myoung-Young (Fire Insurers Laboratories of Korea) ;
  • Jeon, Byoung-Jin (Integrative Cardiovascular Imaging Research Center, Yonsei Cardiovascular Center, College of Medicine, Yonsei University) ;
  • Choi, Hyoung-Gwon (Dept. of Mechanical & Automotive Engineering, Seoul National Univ. of Science & Technology)
  • 최명영 (한국화재보험협회 부설 방재시험연구원) ;
  • 전병진 (연세대학교 의과대학, 심장융합영상연구센터) ;
  • 최형권 (서울과학기술대학교 기계자동차공학과)
  • Received : 2015.12.03
  • Accepted : 2016.02.04
  • Published : 2016.02.29
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Abstract

This paper numerically examines, straight and twisted electrical heat trace installations for their anti-freezing effects on water inside a pipe. The unsteady incompressible Navier-Stokes equations coupled with an energy equation were solved to compare the two installation methods. The heat conduction of the pipe with a heat source interacts with the natural convection of the water, and the conjugate heat transfer was considered using a commercial code (ANSYS-FLUENT) based on a SIMPLE-type algorithm. Numerical experiments, were done to investigate the isotherms and the vector fields in the water region to extract the evolutions of the minimum and maximum temperatures of the water inside the pipe. There was no substantial difference in the anti-freezing effects between the straight and twisted. Therefore, the straight installation is recommended after considering the damage and short circuit behavior of the electrical heat trace.

본 논문에서는 동절기 소방배관의 동파방지를 위한 열선의 직선 시공과 감기 시공의 효과를 수치해석을 통하여 분석하였다. 두 시공법들의 효과 분석을 위하여 3차원 에너지방정식과 비정상 비압축성 Navier-Stokes 방적식의 비정상 해를 구하였다. 수치해석에서 물의 자연대류와 소방 배관의 열전도 방정식이 상호작용을 하므로 복합열전달 해석을 상용코드 ANSYS-FLUENT에서 제공하는 압력-속도 연성기법들 중의 하나인 SIMPLE 알고리즘을 이용하여 수행하였다. 수치해석을 통하여 시간에 따른 배관 내의 유동장 및 온도분포와 배관 내 물의 최대 및 최소온도 변화를 고찰하였다. 수치해석 결과 배관 단위 길이 당 투입열량이 동일한 경우에 감기 시공과 직선 시공의 동파방지 효과는 거의 동일함을 확인하였다. 따라서, 열선 손상과 단락 등을 고려하면 직선 시공이 더 나은 시공법이라 판단된다.

Keywords

References

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