Experimental evaluation of longitudinal and transverse vortex generators on the endwall of a serpentine passage
(2022) In International Journal of Thermal Sciences 176.- Abstract
A 180-deg turning channel can be seen in many heat exchange systems, and a strong three-dimensional flow phenomenon will occur at the turning point. In order to strengthen the heat transfer inside the turn and considering the lack of relevant enhanced endwall heat transfer approach, the present study innovatively demonstrates the measures of enhanced internal endwall heat transfer using arrays of delta-winglet and conical vortex generators. The studied parameters of the vortex generators include aspect ratio (AR), spacing, and angle of attack, etc. The experimental results indicate that the longitudinal vortex generators have more advantages in increasing the heat transfer than the transverse conical vortex generators in certain... (More)
A 180-deg turning channel can be seen in many heat exchange systems, and a strong three-dimensional flow phenomenon will occur at the turning point. In order to strengthen the heat transfer inside the turn and considering the lack of relevant enhanced endwall heat transfer approach, the present study innovatively demonstrates the measures of enhanced internal endwall heat transfer using arrays of delta-winglet and conical vortex generators. The studied parameters of the vortex generators include aspect ratio (AR), spacing, and angle of attack, etc. The experimental results indicate that the longitudinal vortex generators have more advantages in increasing the heat transfer than the transverse conical vortex generators in certain configurations with the same order of magnitude of the increased area. Besides, transverse conical vortex generators are more helpful to improve the endwall heat transfer uniformity than longitudinal vortex generators. The array of longitudinal vortex generators with 45-deg angle of attack, 0.02 m pitch, and 2 aspect ratio provides the highest thermal performance for all studied cases, indicating that the longitudinal delta-winglet vortex generators can induce near-wall flow turbulence as well as convective heat transfer of the endwall with a modest pressure loss penalty. For this optimally designed endwall, the Nusselt number is augmented by up to 35%. From the perspective of energy saving, the present studied vortex generators provide a superior thermal performance at identical pumping power, which can be useful in the future design of endwalls in sharp-turn channels.
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- author
- Zhao, Zhiqi LU ; Luo, Lei ; Qiu, Dandan LU ; Zhou, Xun ; Wang, Zhongqi and Sundén, Bengt LU
- organization
- publishing date
- 2022
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Enhanced convective heat transfer, Liquid crystal thermography, Longitudinal delta-winglet vortex generator, Sharp-turn channel endwall, Transverse conical vortex generator
- in
- International Journal of Thermal Sciences
- volume
- 176
- article number
- 107521
- publisher
- Elsevier
- external identifiers
-
- scopus:85124657647
- ISSN
- 1290-0729
- DOI
- 10.1016/j.ijthermalsci.2022.107521
- language
- English
- LU publication?
- yes
- id
- cab7144a-f2d9-40b3-89d5-245e99902ba7
- date added to LUP
- 2022-04-12 12:00:16
- date last changed
- 2023-11-10 03:50:30
@article{cab7144a-f2d9-40b3-89d5-245e99902ba7,
abstract = {{<p>A 180-deg turning channel can be seen in many heat exchange systems, and a strong three-dimensional flow phenomenon will occur at the turning point. In order to strengthen the heat transfer inside the turn and considering the lack of relevant enhanced endwall heat transfer approach, the present study innovatively demonstrates the measures of enhanced internal endwall heat transfer using arrays of delta-winglet and conical vortex generators. The studied parameters of the vortex generators include aspect ratio (AR), spacing, and angle of attack, etc. The experimental results indicate that the longitudinal vortex generators have more advantages in increasing the heat transfer than the transverse conical vortex generators in certain configurations with the same order of magnitude of the increased area. Besides, transverse conical vortex generators are more helpful to improve the endwall heat transfer uniformity than longitudinal vortex generators. The array of longitudinal vortex generators with 45-deg angle of attack, 0.02 m pitch, and 2 aspect ratio provides the highest thermal performance for all studied cases, indicating that the longitudinal delta-winglet vortex generators can induce near-wall flow turbulence as well as convective heat transfer of the endwall with a modest pressure loss penalty. For this optimally designed endwall, the Nusselt number is augmented by up to 35%. From the perspective of energy saving, the present studied vortex generators provide a superior thermal performance at identical pumping power, which can be useful in the future design of endwalls in sharp-turn channels.</p>}},
author = {{Zhao, Zhiqi and Luo, Lei and Qiu, Dandan and Zhou, Xun and Wang, Zhongqi and Sundén, Bengt}},
issn = {{1290-0729}},
keywords = {{Enhanced convective heat transfer; Liquid crystal thermography; Longitudinal delta-winglet vortex generator; Sharp-turn channel endwall; Transverse conical vortex generator}},
language = {{eng}},
publisher = {{Elsevier}},
series = {{International Journal of Thermal Sciences}},
title = {{Experimental evaluation of longitudinal and transverse vortex generators on the endwall of a serpentine passage}},
url = {{http://dx.doi.org/10.1016/j.ijthermalsci.2022.107521}},
doi = {{10.1016/j.ijthermalsci.2022.107521}},
volume = {{176}},
year = {{2022}},
}