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

Detailed Measurement of Heat/Mass Transfer in a Rotating Two-Pass Duct (II) - Effects of Duct Aspect Ratio -

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

초록

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.

키워드

참고문헌

  1. Park, J. S., Han, J. C., Huang, Y. and Ou, S., 1992, 'Heat Transfer Performance Comparisons of Five Different Rectangular Channels with Parallel Angled Ribs,' Int. J. Heat Transfer, Vol. 35, No. 11, pp. 2891-2903 https://doi.org/10.1016/0017-9310(92)90309-G
  2. Han, J. C., Chandra, P. R. and Lau, S. C., 1988, 'Local Heat/Mass Transfer Distributions Around Sharp 180 Deg Turns in Two-Pass Smooth and Rib-Roughened Channels,' Journal of Heat Transfer, Vol. 110, pp. 91-98 https://doi.org/10.1115/1.3250478
  3. Han, J. C., Park, J. S., Huang, Y. and Ou., S., 1992, 'Heat Transfer Performance Comparisons of Five Different Rectangular Channels with Parallel Angled Ribs,' Int. J. Heat and Mass Transfer, Vol. 35, No. 11, pp. 2891-2903 https://doi.org/10.1016/0017-9310(92)90309-G
  4. Agarwal, P., Achaya, S. and Nikitopoulos, D. E., 2003, 'Heat/Mass Transfer in 1:4 Rectangular Passages with Rotation,' ASME Paper No. GT2003-38615
  5. Sparrow, E. M. and Tao, W. Q., 1983, 'Enhanced Heat Transfer in a Flat Rectangular Duct with Streamwise Periodic Disturbances at One Principal Wall,' Journal of Heat Transfer, Vol. 105, pp. 851-861 https://doi.org/10.1115/1.3245673
  6. Cardone, G., Astarita, T. and Carlomagno, G. M., 1995, 'Surface Flow Visualization Around a 180 Deg Turn Channel for Different Aspect Ratios,' In Flow Visualization VII, Crowder J. ed., Begell House, pp. 977-982
  7. Astarita, T., Cardone, G. and Carlomagno, G. M., 1998, 'Average Heat Transfer Measurements Near a Sharp 180 Degree Turn Channel for Different Aspect Ratios,' IMECHE Conference Transations, Mechanical Engineering Publications, pp. 137-146
  8. Murata, A. and Moschizuki, S., 1999, 'Effect of Cross-Sectional Aspect Ratio on Turbulent Heat Transfer in an Orthogonally Rotating Rectangular Smooth Duct,' Int. J. Heat Mass Transfer, Vol. 42, pp. 3830-3814 https://doi.org/10.1016/S0017-9310(99)00058-7
  9. Murata, A. and Moschizuki, S., 2000, 'Large Eddy Simulation with a Dynamic Subgrid-Scale Model of Turbulent Heat Transfer in an Orthogonally Rotating Rectangular Duct with Transverse Rib Turbulators,' Int. J. Heat Mass Transfer, Vol. 43, pp. 1243-1259 https://doi.org/10.1016/S0017-9310(99)00205-7
  10. Murata, A. and Moschizuki, S., 2003, 'Effect of Cross-Sectional Aspect Ratio on Turbulent Heat Transfer in an Orthogonally Rotating Rectangular Duct with Angled Rib Turbulators,' Int. J. Heat Mass Transfer, Vol. 46, pp. 3119-3133 https://doi.org/10.1016/S0017-9310(03)00080-2
  11. Goldstein, R. J. and Cho, H. H. 1995, 'A Review of Mass Transfer Measurements Using Naphthalene Sublimation,' Experimental Thermal and Fluid Science, Vol. 10, pp. 416-434 https://doi.org/10.1016/0894-1777(94)00071-F
  12. Kline, S. J. and McClintock, F. A., 1953, 'Describing Uncertainty in Single-Sample Experiments,' Mechanical Engineering, Vol. 75, pp. 3-8
  13. McAdams, W. H., 1942, 'Heat Transmission, 2nd Edition,' McGraw-Hill, New York
  14. Chandra, P. R. and Han, J. C., 1989, 'Pressure Drop and Mass Transfer in Two-Pass Ribbed Channels,' J. Thermophysics, Vol. 3, No. 3, pp. 315-320 https://doi.org/10.2514/3.28787