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Turbulent heat transfer characteristics of supercritical n-decane in a vertical tube under various operating pressures

Li, Yong; Sun, Feng; Sunden, Bengt LU and Xie, Gongnan LU (2019) In International Journal of Energy Research
Abstract

To explore the effect of the operating pressure on the flow and thermal characteristics in a vertical tube with supercritical n-decane, the inner wall temperature along the streamwise direction, the applicability of empirical correlations and buoyancy criteria are studied firstly. The mechanisms in views of density distribution, velocity field, turbulence intensity, the thickness of the thermal boundary layer, and secondary flow are then analyzed. It is observed that the buoyancy is helpful for the phenomenon of heat transfer deterioration at lower operating pressures but higher operating pressures can diminish this tendency. According to this reason, the empirical correlation proposed by Bae and Kim is suitable for the higher operating... (More)

To explore the effect of the operating pressure on the flow and thermal characteristics in a vertical tube with supercritical n-decane, the inner wall temperature along the streamwise direction, the applicability of empirical correlations and buoyancy criteria are studied firstly. The mechanisms in views of density distribution, velocity field, turbulence intensity, the thickness of the thermal boundary layer, and secondary flow are then analyzed. It is observed that the buoyancy is helpful for the phenomenon of heat transfer deterioration at lower operating pressures but higher operating pressures can diminish this tendency. According to this reason, the empirical correlation proposed by Bae and Kim is suitable for the higher operating pressures but cannot well predict the occurrence of heat transfer deterioration. However, it can be evaluated by the buoyancy criterion Gr/Re2 = 0.01 qualitatively. The decrease of turbulence intensity, the thickened thermal boundary layer, and secondary flow generation make contributions to the heat transfer deterioration in particular. Similarly, this situation can be diminished and even removed by the higher operating pressures.

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Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
epub
subject
keywords
buoyancy, operating pressure, secondary flow, supercritical n-decane, thermal boundary layer, turbulence intensity
in
International Journal of Energy Research
publisher
John Wiley & Sons
external identifiers
  • scopus:85066885621
ISSN
0363-907X
DOI
10.1002/er.4602
language
English
LU publication?
yes
id
2ac1110c-b42a-44ae-9bc2-9b4fbab1f6fb
date added to LUP
2019-06-25 12:15:00
date last changed
2019-07-16 04:12:30
@article{2ac1110c-b42a-44ae-9bc2-9b4fbab1f6fb,
  abstract     = {<p>To explore the effect of the operating pressure on the flow and thermal characteristics in a vertical tube with supercritical n-decane, the inner wall temperature along the streamwise direction, the applicability of empirical correlations and buoyancy criteria are studied firstly. The mechanisms in views of density distribution, velocity field, turbulence intensity, the thickness of the thermal boundary layer, and secondary flow are then analyzed. It is observed that the buoyancy is helpful for the phenomenon of heat transfer deterioration at lower operating pressures but higher operating pressures can diminish this tendency. According to this reason, the empirical correlation proposed by Bae and Kim is suitable for the higher operating pressures but cannot well predict the occurrence of heat transfer deterioration. However, it can be evaluated by the buoyancy criterion Gr/Re<sup>2</sup> = 0.01 qualitatively. The decrease of turbulence intensity, the thickened thermal boundary layer, and secondary flow generation make contributions to the heat transfer deterioration in particular. Similarly, this situation can be diminished and even removed by the higher operating pressures.</p>},
  author       = {Li, Yong and Sun, Feng and Sunden, Bengt and Xie, Gongnan},
  issn         = {0363-907X},
  keyword      = {buoyancy,operating pressure,secondary flow,supercritical n-decane,thermal boundary layer,turbulence intensity},
  language     = {eng},
  month        = {05},
  publisher    = {John Wiley & Sons},
  series       = {International Journal of Energy Research},
  title        = {Turbulent heat transfer characteristics of supercritical n-decane in a vertical tube under various operating pressures},
  url          = {http://dx.doi.org/10.1002/er.4602},
  year         = {2019},
}