The Effect of U-Bends on the Convective Heat Transfer Coefficient of Nanofluids Flow
Abstract
One effort that can increase the convection heat transfer coefficient between fluid and solid surface is adding nanoparticles to the fluid. However, there are several flow-path conditions, such as concavities and U-turns, can affect the distribution of nanoparticles in the fluid and, in turn, the heat transfer coefficient. This paper studies the effect of a U-turn on the transfer coefficient. The study was conducted using numerical simulations to determine changes in the heat transfer coefficient along the U-turn. It was found that the convection heat transfer coefficient increased at several locations on the outside of the U-turn. The heat transfer coefficient also increased at several locations on the inside of the bend, though by smaller amounts.
##Keywords:##
Nanofluids, Reynolds Number, U-bend, Heat Transfer Coefficient, CFD, Al2O3.
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Published
Mar 30, 2026
How to Cite
ALAMIRSYAH, Alamirsyah; TASRI, Adek.
The Effect of U-Bends on the Convective Heat Transfer Coefficient of Nanofluids Flow.
Journal of Ocean, Mechanical and Aerospace -science and engineering-, [S.l.], v. 70, n. 1, p. 100-107, mar. 2026.
ISSN 2527-6085.
Available at: <https://isomase.org/Journals/index.php/jomase/article/view/632>. Date accessed: 25 july 2026.
doi: http://dx.doi.org/10.36842/jomase.v70i1.632.
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[3] Deeb, R. (2023). New correlations for predicting convective heat transfer of single and multi-row heat exchangers employing staggered drop-shaped tubes. International Journal of Heat and Mass Transfer, 202, 123689.
[4] Ünverdi, M. (2022). Prediction of heat transfer coefficient and friction factor of mini channel shell and tube heat exchanger using numerical analysis and experimental validation. International Journal of Thermal Sciences, 171, 107182.
[5] Alami, A. H., Ramadan, M., Tawalbeh, M., Haridy, S., Al Abdulla, S., Aljaghoub, H., ... & Olabi, A. G. (2023). A critical insight on nanofluids for heat transfer enhancement. Scientific Reports, 13(1), 15303.
[6] Sundar, L. S., Kumar, N. R., Addis, B. M., Bhramara, P., Singh, M. K. & Sousa, A. C. (2019). Heat transfer and effectiveness experimentally-based analysis of wire coil with core-rod inserted in Fe3O4/water nanofluid flow in a double pipe U-bend heat exchanger. International Journal of Heat and Mass Transfer, 134, 405-419.
[7] Barai, R., Kumar, D. & Wankhade, A. (2021). Heat transfer performance of nanofluids in heat exchanger: a review. Journal of Thermal Engineering, 9(1), 86-106.
[8] Ukueje, W. E., Abam, F. I. & Obi, A. (2022). A perspective review on thermal conductivity of hybrid nanofluids and their application in automobile radiator cooling. Journal of Nanotechnology, 2022(1), 2187932.
[9] Tao, Q., Zhong, F., Deng, Y., Wang, Y. & Su, C. (2023). A review of nanofluids as coolants for thermal management systems in fuel cell vehicles. Nanomaterials, 13(21), 2861.
[10] Thesiya, D., Patel, H. & Patange, G. S. (2023). A comprehensive review electronic cooling: a nanomaterial perspective. International Journal of Thermofluids, 19, 100382.
[11] Pak, B. C. & Cho, Y. I. (1998). Hydrodynamic and heat transfer study of dispersed fluids with submicron metallic oxide particles. Experimental Heat Transfer an International Journal, 11(2), 151-170, doi: 10.1080/08916159808946559.
[12] Gabir, M. M., Albayati, I. M., Hatami, M. & Alkhafaji, D. (2024). An experimental investigation of the convective heat transfer augmentation in U-bend double pipe heat exchanger using water-MgO-Cmc fluid. Scientific Reports, 14(1), 12442, doi: 10.1038/s41598-024-63043-6.
[13] Clarke, R. & Finn, D. (2008). Numerical investigation of the influence of heat exchanger U-bends on temperature profile and heat transfer of secondary working fluids. The 5th European Thermal-Sciences Conference, Eindhoven, the Netherlands, 18-22 May 2008.
[14] Rao, V. N. & Sankar, B. R. (2017). CFD analysis of CuO/water nanofluid flow in a double pipe U-Bend heat exchanger. International Journal of Dynamic of Fluid, 13(1), 137-152..
[15] Alguacil, F. J. & Alonso, M. (2024). The motion of Brownian particles suspended in a non-uniform fluid flow. Journal of Aerosol Science, 179, 106382.
[16] Bacha, H. B., Ullah, N., Hamid, A. & Shah, N. A. (2024). A comprehensive review on nanofluids: Synthesis, cutting-edge applications, and future prospects. International Journal of Thermofluids, 22, 100595, doi: 10.1016/j.ijft.2024.100595.
[17] Cengel, Y. A., Klein, S. & Beckman, W. (1998). Heat Transfer: A Practical Approach (Vol. 141). Boston: WBC McGraw-Hill.
[18] Schlichting, H. & Gersten, K. (2016). Boundary-layer theory. Springer Berlin Heidelberg, doi: 10.1007/978-3-662-52919-5.
[19] Chassagne, F., Barbour, M. C., Chivukula, V. K., Machicoane, N., Kim, L. J., Levitt, M. R. & Aliseda, A. (2021). The effect of Dean, Reynolds and Womersley numbers on the flow in a spherical cavity on a curved round pipe. Part 1. Fluid mechanics in the cavity as a canonical flow representing intracranial aneurysms. Journal of Fluid Mechanics, 915, doi: 10.1017/jfm.2020.1114.
