Aspect ratio of thermo-hydraulic performance of periodically prescribed semi-circular groove in rectangular channel

Authors

  • Samson A. Aasa
    Department of Mechanical and Mechatronic Engineering, Faculty of Engineering and the Built Environment, Tshwane University of Technology, South Africa
  • Regan K. Dunne
    Department of Mechanical and Mechatronic Engineering, Faculty of Engineering and the Built Environment, Tshwane University of Technology, South Africa
  • Dawood A. Desai
    Department of Mechanical and Mechatronic Engineering, Faculty of Engineering and the Built Environment, Tshwane University of Technology, South Africa

Keywords:

Convective heat enhancement, Artificial technique, Semi-circular groove, Friction factor, Nusselt number

Abstract

A rectangular channel including an angled groove on the end wall was modeled in an air tunnel to assess the augmentation of heat transfer and the friction factor.  The groove exhibited a 45-degree angle relative to the flow direction, with a pitch-to-groove depth ratio of 6.5.  Three distinct aspect ratios, 0.025, 0.03, and 0.05, were evaluated.  The Reynolds number varied from 1000 to 11000, including laminar to turbulent flow regimes.  The pressure reduction and thermal transfer were quantified in the primary flow of the experimental portion.  The 0.05 aspect ratio yielded the highest performance, with optimal values of 22%, 30%, and 48% in the laminar, transition, and turbulent areas, respectively.  The non-dimensional air temperature of the flow at the conclusion of the test portion demonstrated the dispersion of the fluid, signifying uniform turbulence within the channel.  The impacts of various plate factors on enhancing heat transmission were regulated.  This was ascribed to the channel aspect ratio, mild pressure penalties, and the significant thermal increases of the groove endwalls.  It reduced the thickness of the fluid layer at the surface, facilitated prolonged smooth flow over the groove surfaces, and is essential for enhancing the efficiency and sizing of flat plate heat exchangers in applications such as solar panels, fuel cells, electronic components, motor/generator jackets, bearing jackets, and turbine blades.  The findings indicated that angled grooves can be beneficial in several contemporary applications, including turbine blades, solar cells, and processing equipment.

Dimensions

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Air temperature slot at the top endwall.

Published

2025-12-22

How to Cite

Aspect ratio of thermo-hydraulic performance of periodically prescribed semi-circular groove in rectangular channel. (2025). African Scientific Reports, 4(3), 205. https://doi.org/10.46481/asr.2025.4.3.205

Issue

Volume 4, Issue 3, December 2025 (In Progress)

Section

ENGINEERING SECTION
Copyright & Licensing

Copyright (c) 2025 Samson A. Aasa, Regan K. Dunne, Dawood A. Desai

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.

How to Cite

Aspect ratio of thermo-hydraulic performance of periodically prescribed semi-circular groove in rectangular channel. (2025). African Scientific Reports, 4(3), 205. https://doi.org/10.46481/asr.2025.4.3.205