Numerical Investigation of a New Segmented Annular Ring Tube for Heat Transfer Enhancement in Solar Water Heating Systems

Mohamed Said Kahaleras (), Sabbah Ataya (), Lina Chouichi, Yacine Karmi, Omar Reffas, Issam Bousba, Abdessalam Otmani and Haithem Boumediri
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Mohamed Said Kahaleras: Laboratory of Energy Systems Technologies (LTSE), Department of Process Engineering and Energetics, National Higher School of Technology and Engineering, Annaba 23005, Algeria
Sabbah Ataya: Department of Mechanical Engineering, Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh 11432, Saudi Arabia
Lina Chouichi: Laboratory of Energy Systems Technologies (LTSE), Department of Process Engineering and Energetics, National Higher School of Technology and Engineering, Annaba 23005, Algeria
Yacine Karmi: Mechanical Department, Institute of Applied Sciences and Technologies, University of Constantine 1, Constantine 25017, Algeria
Omar Reffas: Mechanical Department, Institute of Applied Sciences and Technologies, University of Constantine 1, Constantine 25017, Algeria
Issam Bousba: Faculty of Sciences and Technology, University of Jijel, Jijel 18000, Algeria
Abdessalam Otmani: Laboratory of Energy Systems Technologies (LTSE), Department of Process Engineering and Energetics, National Higher School of Technology and Engineering, Annaba 23005, Algeria
Haithem Boumediri: Mechanical Department, Institute of Applied Sciences and Technologies, University of Constantine 1, Constantine 25017, Algeria

Energies, 2025, vol. 18, issue 21, 1-18

Abstract: This study presents a numerical investigation of a parabolic trough absorber tube equipped with a novel Angularly Segmented Ring Turbulator (ASRT), designed to enhance heat transfer through periodic flow disturbance and improved wall–fluid interaction. The proposed ASRT geometry consists of segmented annular rings arranged along the tube length, characterized by two key parameters: the number of angular segments per ring ( Nr = 4, 6, 8) and the angular spacing of each segment ( α = 20° and 40°). Three dimensional simulations were performed using the finite volume method under turbulent flow conditions, with Reynolds numbers ranging from 3300 to 11,000. A non-uniform solar heat flux, obtained via Monte Carlo Ray Tracing (MCRT), was applied as a boundary condition at the outer wall to replicate realistic solar concentration. The results reveal that the ASRT significantly improves convective heat transfer, with the Nusselt number ratio N u / N u s reaching up to 3.7 for α = 20° and Nr = 8. This enhancement is accompanied by a moderate rise in the friction factor ratio f / f s , reaching approximately 7.5 at Re = 3300, indicating efficient turbulence promotion with acceptable hydraulic penalties. The Performance Evaluation Criterion ( PEC ) ranges from 1.7 to 1.9, confirming the superiority of ASRT over the smooth tube.

Keywords: parabolic trough collector; absorber tube; angularly-segmented ring turbulator (ASRT); CFD simulation; performance evaluation criterion ( PEC ) (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2025
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