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Thermo-Hydraulic Performance Enhancement of Finned Elliptical Tube Heat Exchangers by Utilizing Innovative Dimple Turbulators

Lotfi, Babak and Sundén, Bengt LU (2019) In Heat Transfer Engineering
Abstract

As a new type of fin structure in finned tube heat exchangers, dimple turbulators exhibit excellent potential for thermo-hydraulic performance enhancement. A three-dimensional numerical simulation study was conducted to investigate the influences of five kinds of innovative concave dimple turbulators (CDTs), namely–elliptical dimple, conical frustum dimple, trapezoidal prism dimple, leeward triangular dimple and upward triangular dimple (UwTD) on the thermo-hydraulic performance enhancement in a plate fin-and-elliptical tube (PFET) heat exchanger, where CDTs are textured on the fin surface transversely between the elliptical tubes. The computational results are analyzed by considering the performance evaluation criterion for the PFET... (More)

As a new type of fin structure in finned tube heat exchangers, dimple turbulators exhibit excellent potential for thermo-hydraulic performance enhancement. A three-dimensional numerical simulation study was conducted to investigate the influences of five kinds of innovative concave dimple turbulators (CDTs), namely–elliptical dimple, conical frustum dimple, trapezoidal prism dimple, leeward triangular dimple and upward triangular dimple (UwTD) on the thermo-hydraulic performance enhancement in a plate fin-and-elliptical tube (PFET) heat exchanger, where CDTs are textured on the fin surface transversely between the elliptical tubes. The computational results are analyzed by considering the performance evaluation criterion for the PFET heat exchangers with different types of CDT shapes. The present investigation demonstrates that the heat transfer enhancement is intimately pertained to ejection with longitudinal counter-rotating flow, strengthened secondary flow and vortex structures at the downstream rim of CDT. A parametric study on the CDTs indicated that the UwTD vortex turbulators give better thermo-hydraulic performance under the present conditions. The numerical simulation results illustrated different secondary flow structures and heat transfer characteristics of the CDTs with various shapes, which disclosed the influential mechanisms of differently shaped dimple turbulators on the heat transfer augmentation in PFET heat exchangers.

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author
organization
publishing date
type
Contribution to journal
publication status
epub
subject
in
Heat Transfer Engineering
publisher
Taylor & Francis
external identifiers
  • scopus:85068203615
ISSN
0145-7632
DOI
10.1080/01457632.2019.1611132
language
English
LU publication?
yes
id
902a74de-c41e-4d7e-bd6a-6ebd3c4f120d
date added to LUP
2019-07-10 16:05:11
date last changed
2020-04-02 02:38:05
@article{902a74de-c41e-4d7e-bd6a-6ebd3c4f120d,
  abstract     = {<p>As a new type of fin structure in finned tube heat exchangers, dimple turbulators exhibit excellent potential for thermo-hydraulic performance enhancement. A three-dimensional numerical simulation study was conducted to investigate the influences of five kinds of innovative concave dimple turbulators (CDTs), namely–elliptical dimple, conical frustum dimple, trapezoidal prism dimple, leeward triangular dimple and upward triangular dimple (UwTD) on the thermo-hydraulic performance enhancement in a plate fin-and-elliptical tube (PFET) heat exchanger, where CDTs are textured on the fin surface transversely between the elliptical tubes. The computational results are analyzed by considering the performance evaluation criterion for the PFET heat exchangers with different types of CDT shapes. The present investigation demonstrates that the heat transfer enhancement is intimately pertained to ejection with longitudinal counter-rotating flow, strengthened secondary flow and vortex structures at the downstream rim of CDT. A parametric study on the CDTs indicated that the UwTD vortex turbulators give better thermo-hydraulic performance under the present conditions. The numerical simulation results illustrated different secondary flow structures and heat transfer characteristics of the CDTs with various shapes, which disclosed the influential mechanisms of differently shaped dimple turbulators on the heat transfer augmentation in PFET heat exchangers.</p>},
  author       = {Lotfi, Babak and Sundén, Bengt},
  issn         = {0145-7632},
  language     = {eng},
  month        = {06},
  publisher    = {Taylor & Francis},
  series       = {Heat Transfer Engineering},
  title        = {Thermo-Hydraulic Performance Enhancement of Finned Elliptical Tube Heat Exchangers by Utilizing Innovative Dimple Turbulators},
  url          = {http://dx.doi.org/10.1080/01457632.2019.1611132},
  doi          = {10.1080/01457632.2019.1611132},
  year         = {2019},
}