Natural convection heat transfer of supercritical binary fluid in a long closed vertical cylinder

Z. Q. Long, P. Zhang, B. Shen

研究成果: ジャーナルへの寄稿学術誌査読

6 被引用数 (Scopus)

抄録

We study the natural convection heat transfer of supercritical N2-Ar binary fluid in a closed vertical cylinder with an aspect ratio of 27 in the Rayleigh number range of 9.0 × 1011-2.0 × 1014. The cylinder is heated at the lower part and cooled from the top surface. The composition of the binary fluid and the average temperature of the cold part of the cylinder are varied to investigate the heat transfer characteristics of natural convection. Three different regimes are found with the increase of Ra, i.e., Laminar thermal boundary layer (TBL) regime, Transition regime, and Ultimate regime, with the two critical Rayleigh numbers determined experimentally to be Racrit1 ≈ 4.0 × 1013 and Racrit2 ≈ 1.14 × 1014, respectively. The scalings of natural convection in the Laminar TBL regime and Ultimate regime are Nu ∝ Ra0.22 and Nu ∝ Ra1/3, respectively. When natural convection experiences near-critical temperature range, the drastic variations of the thermo-physical properties lead to an anomalous phenomenon where an inflection appears in the Nu-Ra correlation with an increase in heat transfer rate, and the corresponding temperature of the inflection point becomes higher for the fluid with higher critical temperature. The binary components in the fluid show no apparent effect on the heat transfer characteristics of natural convection except affecting the corresponding temperature of the inflection point in the present study, and the binary fluid behaves as a pseudo-pure fluid (an assumed pure fluid with the same thermo-physical properties as the corresponding binary fluid).

本文言語英語
ページ(範囲)551-561
ページ数11
ジャーナルInternational Journal of Heat and Mass Transfer
80
DOI
出版ステータス出版済み - 1月 2015
外部発表はい

!!!All Science Journal Classification (ASJC) codes

  • 凝縮系物理学
  • 機械工学
  • 流体および伝熱

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