Heat Transfer Performance and Flow Characteristics of a Heat Exchange Tube with Isosceles Trapezoidal Winglet Longitudinal Vortex Generators

The thermal-hydraulic performance of circular heat transfer tubes equipped with isosceles trapezoidal winglet longitudinal vortex generators (ITWL-VGs) was investigated through integrated experimental and numerical approaches. Experimental studies were conducted that focused on the effects of key pa...

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Bibliographic Details
Main Authors: Lin Liu, Zhichun Ni, Haoyuan Tang, Hui Xu, Bingyun Jiang
Format: Article
Language:English
Published: MDPI AG 2025-03-01
Series:Energies
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Online Access:https://www.mdpi.com/1996-1073/18/7/1717
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Summary:The thermal-hydraulic performance of circular heat transfer tubes equipped with isosceles trapezoidal winglet longitudinal vortex generators (ITWL-VGs) was investigated through integrated experimental and numerical approaches. Experimental studies were conducted that focused on the effects of key parameters: (1) the ITW quantity (<i>n</i> = 4, 6, 8); (2) the attack angle (α = 0°, 15°, 30°, 45°); and (3) four distinct VG arrangements. Numerical simulations employing multi-physical field analysis elucidated the underlying heat transfer enhancement mechanisms. The numerical simulations demonstrated excellent agreement with the experimental measurements. The results indicated that uniformly distributed ITWL-VGs with suitable angles of attack (α) significantly enhanced the thermal performance. Increasing the number of ITWs (<i>N</i>) generated additional longitudinal vortices, intensifying fluid mixing and heat transfer enhancement, thereby improving the <i>PEC</i> value. All the Nusselt number (<i>Nu</i>), friction factor (<i>f</i>) and <i>PEC</i> values exhibited positive correlations with the <i>α</i> and the spacing (<i>L<sub>P</sub></i>), respectively. Within the scope of this study, the <i>α</i> should not be less than 30°. In addition, an optimal value should be used for the <i>L<sub>P</sub></i>. The maximum <i>PEC</i> value was 1.27. These findings conclusively demonstrated the significant heat transfer enhancement capabilities of ITWL-VGs.
ISSN:1996-1073