Transactions of the Korean Society of Mechanical Engineers B (대한기계학회논문집B)

The Korean Society of Mechanical Engineers (대한기계학회)
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Numerical Study of Thermo-Fluid Features of Electrically Conducting Fluids in Tube Bank Heat Exchangers Exposed to Uniform Magnetic Fields

관군 열교환기에서 균일 자기장에 의한 전기 전도성 유체의 열유동 특성에 관한 수치해석 연구

  • Oh, Jin Ho (Dept. of Mechanical Engineering, Kyungpook Nat'l Univ.) ;
  • Kang, Namcheol (School of Mechanical Engineering, Kyungpook Nat'l Univ.) ;
  • Park, Il Seouk (School of Mechanical Engineering, Kyungpook Nat'l Univ.)
  • 오진호 (경북대학교 기계공학과) ;
  • 강남철 (경북대학교 기계공학부) ;
  • 박일석 (경북대학교 기계공학부)
  • Received : 2017.04.03
  • Accepted : 2017.07.18
  • Published : 2017.10.01
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Abstract

When an electrically conducting fluid flows through a staggered tube bank, the heat transfer and fluid flow features are changed by the externally introduced magnetic field. This study provides a numerical investigation of this phenomenon. Heat and fluid flows are investigated for unsteady laminar flows at Reynolds numbers of 50 and 100 with the Hartmann number gradually increasing from zero to 100. As the Hartmann number increases, and owing to the effects of the introduced magnetic field, the velocity boundary layer near the tube wall is thinned, the flow separation is delayed downstream, and the shrinkage of a recirculation zone formed near the rear side is observed. Based on these thermo-fluid deformations, the resulting changes in the local and average Nusselt number are investigated.

본 연구에서는 엇갈림 배열 관군 사이를 전기 전도성 유체가 흐를 때 외부에서 인가한 자기장의 영향으로 변화하는 열유동 특성을 수치해석적으로 연구하였다. Reynolds 수 50과 100의 비정상 층류 관군 유동에서 외부 인가 자기장의 세기를 의미하는 Hartmann 수를 0에서 100까지 점진적으로 변화시킴에 따라 관군 내부의 열유동 특성을 관찰하였다. Hartmann 수가 증가함에 따라 인가 자기장의 영향으로 관표면의 속도 경계층이 얇아지고, 유동 박리를 후류로 지연시키며, 관 후면에 형성되는 재순환 영역의 크기가 줄어드는 것을 관찰하였다. 최종적으로 열유동 변형에 의한 결과적 국소 및 평균 Nusselt 수 변화 특성을 제시하였다.

Keywords

References

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