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Numerical investigation of entropy generation of turbulent flow in a novel outward corrugated tube

Wang, Wei LU ; Zhang, Yaning; Liu, Jian LU ; Li, Bingxi and Sundén, Bengt LU (2018) In International Journal of Heat and Mass Transfer 126. p.836-847
Abstract

The present study numerically investigates the second law analysis of turbulent flow in novel outward helical corrugated tubes by using a Reynolds Stress Model (RSM). A case of a transverse corrugated tube and five cases of helical corrugated tubes with different height-to-diameter ratios and pitch-to-diameter ratios are examined with Reynolds number ranging from 3800 to 43,800 at a constant wall temperature condition. The results indicate that the secondary flow significantly increases the thermal and viscous dissipation irreversibilities. However, the spiral flow inhibits the secondary flow and the production of local entropy. The heat transfer effective zone (Belocal > 0.5) is mainly located at the sub-layer and... (More)

The present study numerically investigates the second law analysis of turbulent flow in novel outward helical corrugated tubes by using a Reynolds Stress Model (RSM). A case of a transverse corrugated tube and five cases of helical corrugated tubes with different height-to-diameter ratios and pitch-to-diameter ratios are examined with Reynolds number ranging from 3800 to 43,800 at a constant wall temperature condition. The results indicate that the secondary flow significantly increases the thermal and viscous dissipation irreversibilities. However, the spiral flow inhibits the secondary flow and the production of local entropy. The heat transfer effective zone (Belocal > 0.5) is mainly located at the sub-layer and buffer-layer, and the ineffective zone (Belocal < 0.2) is located at the turbulent severe pulsation zone. A comprehensive consideration of the total entropy generation number (Ns-tot) and average Bejan number (Beave) indicates that the optimal Re is less than 31,000 for all the cases although Re does not exceed 18,800 in the case of Hl/D = 0.15, pl/D = 1.0 and Hl/D = 0.10, pl/D = 0.5. Additionally, the helical corrugated tube exhibits an overall advantage when compared with a transverse corrugated tube with the same geometrical parameters.

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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Detached vortex, Local entropy generation, Outward corrugated tube, Second-law analysis, Spiral flow, Useful energy utilization
in
International Journal of Heat and Mass Transfer
volume
126
pages
12 pages
publisher
Pergamon
external identifiers
  • scopus:85048312245
ISSN
0017-9310
DOI
10.1016/j.ijheatmasstransfer.2018.06.017
language
English
LU publication?
yes
id
295ca0db-df64-4ebd-bcd8-bc964d5dd83e
date added to LUP
2018-06-25 13:18:09
date last changed
2019-01-06 13:58:23
@article{295ca0db-df64-4ebd-bcd8-bc964d5dd83e,
  abstract     = {<p>The present study numerically investigates the second law analysis of turbulent flow in novel outward helical corrugated tubes by using a Reynolds Stress Model (RSM). A case of a transverse corrugated tube and five cases of helical corrugated tubes with different height-to-diameter ratios and pitch-to-diameter ratios are examined with Reynolds number ranging from 3800 to 43,800 at a constant wall temperature condition. The results indicate that the secondary flow significantly increases the thermal and viscous dissipation irreversibilities. However, the spiral flow inhibits the secondary flow and the production of local entropy. The heat transfer effective zone (Be<sub>local</sub> &gt; 0.5) is mainly located at the sub-layer and buffer-layer, and the ineffective zone (Be<sub>local</sub> &lt; 0.2) is located at the turbulent severe pulsation zone. A comprehensive consideration of the total entropy generation number (N<sub>s-tot</sub>) and average Bejan number (Be<sub>ave</sub>) indicates that the optimal Re is less than 31,000 for all the cases although Re does not exceed 18,800 in the case of Hl/D = 0.15, pl/D = 1.0 and Hl/D = 0.10, pl/D = 0.5. Additionally, the helical corrugated tube exhibits an overall advantage when compared with a transverse corrugated tube with the same geometrical parameters.</p>},
  author       = {Wang, Wei and Zhang, Yaning and Liu, Jian and Li, Bingxi and Sundén, Bengt},
  issn         = {0017-9310},
  keyword      = {Detached vortex,Local entropy generation,Outward corrugated tube,Second-law analysis,Spiral flow,Useful energy utilization},
  language     = {eng},
  month        = {11},
  pages        = {836--847},
  publisher    = {Pergamon},
  series       = {International Journal of Heat and Mass Transfer},
  title        = {Numerical investigation of entropy generation of turbulent flow in a novel outward corrugated tube},
  url          = {http://dx.doi.org/10.1016/j.ijheatmasstransfer.2018.06.017},
  volume       = {126},
  year         = {2018},
}