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Numerical investigation on flow and thermal performance of supercritical CO 2 in horizontal cylindrically concaved tubes

Li, Yong ; Sun, Feng ; Xie, Gongnan LU ; Sunden, Bengt LU and Qin, Jiang (2019) In Applied Thermal Engineering 153. p.655-668
Abstract


To improve the overall heat transfer of supercritical carbon dioxide (SCO
2
) in a horizontal circular tube, this study proposes a novel kind of tube with cylindrically concaves and fillets on the circular surface. Several tubes are designed accordingly to investigate various parameters like θ (sectorial angle of concaves), r
2
(radius of concaves), r
... (More)


To improve the overall heat transfer of supercritical carbon dioxide (SCO
2
) in a horizontal circular tube, this study proposes a novel kind of tube with cylindrically concaves and fillets on the circular surface. Several tubes are designed accordingly to investigate various parameters like θ (sectorial angle of concaves), r
2
(radius of concaves), r
3
(radius of fillets) and n (number of concaves) to observe their effects on the thermal performance. The heat transfer and pressure drop characteristics of SCO
2
in these tubes are conducted by applying a verified turbulence model at an operation pressure of 8.0 MPa, an inlet temperature of 323.15 K, a mass flow rate of 0.005652 kg/s and a heat power rate of 565.488 W. It is found that the heat transfer coefficient of all the designed cases are improved due to the secondary flow and the maximum value of the h/h
4
/(f/f
4
) is 1.134 compared with that of the standard case 4, while the friction factors are not increased but in fact even lower without raising the vortex pairs. Finally, the heat transfer coefficient at the vicinity of the pseudo-critical point is studied and it is noted that the heat transfer is also enhanced at this region.

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author
; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Cylindrically concaved tubes, Heat transfer, Parametrical study, Pressure drop, Supercritical carbon dioxide
in
Applied Thermal Engineering
volume
153
pages
14 pages
publisher
Elsevier
external identifiers
  • scopus:85062804176
ISSN
1359-4311
DOI
10.1016/j.applthermaleng.2019.03.034
language
English
LU publication?
yes
id
a67b32e1-cc45-4332-a6c2-e84be47b1419
date added to LUP
2019-03-19 09:11:57
date last changed
2020-10-11 05:56:45
@article{a67b32e1-cc45-4332-a6c2-e84be47b1419,
  abstract     = {<p><br>
                                                         To improve the overall heat transfer of supercritical carbon dioxide (SCO                             <br>
                            <sub>2</sub><br>
                                                         ) in a horizontal circular tube, this study proposes a novel kind of tube with cylindrically concaves and fillets on the circular surface. Several tubes are designed accordingly to investigate various parameters like θ (sectorial angle of concaves), r                             <br>
                            <sub>2</sub><br>
                                                          (radius of concaves), r                             <br>
                            <sub>3</sub><br>
                                                          (radius of fillets) and n (number of concaves) to observe their effects on the thermal performance. The heat transfer and pressure drop characteristics of SCO                             <br>
                            <sub>2</sub><br>
                                                          in these tubes are conducted by applying a verified turbulence model at an operation pressure of 8.0 MPa, an inlet temperature of 323.15 K, a mass flow rate of 0.005652 kg/s and a heat power rate of 565.488 W. It is found that the heat transfer coefficient of all the designed cases are improved due to the secondary flow and the maximum value of the h/h                             <br>
                            <sub>4</sub><br>
                                                         /(f/f                             <br>
                            <sub>4</sub><br>
                                                         ) is 1.134 compared with that of the standard case 4, while the friction factors are not increased but in fact even lower without raising the vortex pairs. Finally, the heat transfer coefficient at the vicinity of the pseudo-critical point is studied and it is noted that the heat transfer is also enhanced at this region.                         <br>
                        </p>},
  author       = {Li, Yong and Sun, Feng and Xie, Gongnan and Sunden, Bengt and Qin, Jiang},
  issn         = {1359-4311},
  language     = {eng},
  pages        = {655--668},
  publisher    = {Elsevier},
  series       = {Applied Thermal Engineering},
  title        = {Numerical investigation on flow and thermal performance of supercritical CO                         
                        <sub>2</sub>
                                                  in horizontal cylindrically concaved tubes},
  url          = {http://dx.doi.org/10.1016/j.applthermaleng.2019.03.034},
  doi          = {10.1016/j.applthermaleng.2019.03.034},
  volume       = {153},
  year         = {2019},
}