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

The Korean Society of Mechanical Engineers (대한기계학회)
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Detailed Measurement of Heat/Mass Transfer in a Rotating Two-Pass Duct (II) - Effects of Duct Aspect Ratio -

이차 냉각 유로를 가진 회전덕트에서 열/물질전달 특성 (II) - 덕트 종횡비에 따른 영향 -

  • 김경민 (연세대학교 대학원 기계공학과) ;
  • 김윤영 (연세대학교 대학원 기계공학과) ;
  • 이동호 (연세대학교 대학원 기계공학과) ;
  • 조형희 (연세대학교 기계공학과)
  • Published : 2004.08.01
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Abstract

Measurements of local heat/mass transfer coefficients in rotating two-pass ducts are presented. Ducts of three different aspect ratios (W/H), 0.5, 1.0 and 2.0, are employed with a fixed hydraulic diameter ($D_h$) of 26.7 nm. $90^{\circ}$-rib turbulators are attached on the leading and trailing walls symmetrically. The rib height-to-hydraulic diameter ratio ($e/D_h$) is 0.056, and the rib pitch-to-rib height ratio (p/e) is 10. The experimental conditions are the same as those of the previous part of the study. As the rib height-to-duct height ratio (e/H) increases, the core flow is more disturbed and accelerated in the midsections of ribs. Therefore, the obtained data show higher heat/mass transfer in the higher aspect ratio duct. Dean vortices also augment heat/mass transfer in the turn and in the upstream region of the second pass. However, the effect becomes less significant for the higher aspect ratio because the surface area increases in the present geometric condition. The effect of rotation produces heat/mass transfer discrepancy.

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References

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