Impact of Conical and Fusiform Turbulators on Heat Transfer Enhancement and Pressure Drop Inside a Double-Tube Heat Exchanger

Year 2025, Volume: 28 Issue: 3, 142 - 151, 01.09.2025

Abdelaziz Begag , Amel Bouregueba , Said A Bboudi , Rachid Saim

https://doi.org/10.5541/ijot.1675049

Abstract

This study focuses on enhancing heat transfer in a concentric double-tube heat exchanger by incorporating internal turbulators of two distinct geometries: conical and fusiform. The study numerically investigates the impact of these turbulators, placed within the inner tube, on turbulent flow and thermal performance over a Reynolds number range of 4000 to 12,000. A numerical study was carried out using ANSYS Fluent 16.0 software, where the governing equations were solved by the finite volume method. The Realizable k–ε turbulence model was used to capture the effects of turbulence on the flow field. Key performance indicators such as the Nusselt number and pressure drop were analyzed for both configurations. The results reveal that fusiform turbulators provide superior thermal enhancement, increasing the average Nusselt number by up to 34% compared to a smooth tube. However, this enhancement is accompanied by a significant increase in pressure drop across all tested cases, underlining the trade-off between heat transfer improvement and flow resistance. These findings demonstrate the effectiveness of fusiform geometries in improving the thermohydraulic efficiency of tubular heat exchangers.

Keywords

Turbulator , heat exchanger , double-tube , heat transfer enhancement

References

• S. D. Shelare, K. R. Aglawe, and P. N. Belkhode, "A review on twisted tape inserts for enhancing the heat transfer," Materials Today: Proceedings, vol. 54, pp. 560-565, 2022, doi: 10.1016/j.matpr.2021.09.01
• J.-S. Yu, J.-H. Kim, and J.-T. Kim, "Effect of triangular baffle arrangement on heat transfer enhancement of air-type PVT collector," Sustainability, vol. 12, no. 18, p. 7469, 2020, doi: 10.3390/su12187469
• M. Kılıç, "Numerical investigation of heat transfer from a porous plate with transpiration cooling," Journal of Thermal Engineering, vol. 4, no. 1, pp. 1632-1647, 2018, doi: 10.18186/journal-of-thermal-engineering.362048
• M. Kilic, M. Sahin, and A. Abdulvahitoglu, "A new approach for enhancing the effectiveness of a regenerative heat exchanger by using organic and inorganic phase change material," Journal of Thermal Analysis and Calorimetry, vol. 149, no. 22, pp. 13081-13093, 2024, doi: 10.1007/s10973-024-13599-2
• R. Aghayari, H. Maddah, S. M. Pourkiaei, M. H. Ahmadi, L. Chen, and M. Ghazvini, "Theoretical and experimental studies of heat transfer in a double-pipe heat exchanger equipped with twisted tape and nanofluid," The European Physical Journal Plus, vol. 135, pp. 1-26, 2020, doi: 10.1140/epjp/s13360-020-00252-8
• E. Khodabandeh, M. Bahiraei, R. Mashayekhi, B. Talebjedi, and D. Toghraie, "Thermal performance of Ag–water nanofluid in tube equipped with novel conical strip inserts using two-phase method: geometry effects and particle migration considerations," Powder technology, vol. 338, pp. 87-100, 2018, doi: 10.1016/j.powtec.2018.06.038
• M. M. Ibrahim, M. A. Essa, and N. H. Mostafa, "A computational study of heat transfer analysis for a circular tube with conical ring turbulators," International Journal of Thermal Sciences, vol. 137, pp. 138-160, 2019, doi: 10.1016/j.ijthermalsci.2018.10.028
• M. Sheikholeslami, M. Jafaryar, D. D. Ganji, and Z. Li, "Exergy loss analysis for nanofluid forced convection heat transfer in a pipe with modified turbulators," Journal of Molecular Liquids, vol. 262, pp. 104-110, 2018, doi: 10.1016/j.molliq.2018.04.077
• S. Sammil and M. Sridharan, "Employing ensemble machine learning techniques for predicting the thermohydraulic performance of double pipe heat exchanger with and without turbulators," Thermal Science and Engineering Progress, vol. 47, 2024, doi: 10.1016/j.tsep.2023.102337
• J. Luo et al., "Thermal-frictional behavior of new special shape twisted tape and helical coiled wire turbulators in engine heat exchangers system," Case Studies in Thermal Engineering, vol. 53, 2024, doi: 10.1016/j.csite.2023.103877
• U. Akdag, S. Akcay, N. Un, and M. Danismaz, "Experimental investigation of the heat transfer characteristics of a synthetic annular jet impingement on a flat surface," Experimental Heat Transfer, pp. 1-20, 2024, doi: 10.1080/08916152.2024.2356165
• H. Chen, H. Ayed, R. Marzouki, F. Emami, I. Mahariq, and F. Jarad, "Thermal, hydraulic, exergitic and economic evaluation of a flat tube heat exchanger equipped with a plain and modified conical turbulator," Case Studies in Thermal Engineering, vol. 28, 2021, doi: 10.1016/j.csite.2021.101587.
• A. N. Özakın, "CFD analysis of using umbrella shaped turbulators to improve heat transfer in a horizontal pipe," International Journal of Innovative Research and Reviews, vol. 6, no. 1, pp. 30-34, 2022.
• M. Danışmaz and M. Demirbilek, "Assessment of heat transfer capabilities of some known nanofluids under turbulent flow conditions in a five-turn spiral pipe flow," Applied Rheology, vol. 34, no. 1, 2024, doi: 10.1515/arh-2024-0002.
• M. F. Hasan, M. Danışmaz, and B. M. Majel, "Thermal performance investigation of double pipe heat exchanger embedded with extended surfaces using nanofluid technique as enhancement," Case Studies in Thermal Engineering, vol. 43, 2023, doi: 10.1016/j.csite.2023.102774.
• F. Oflaz, O. Keklikcioglu, and V. Ozceyhan, "Investigating thermal performance of combined use of SiO2-water nanofluid and newly designed conical wire inserts," Case Studies in Thermal Engineering, vol. 38, 2022, doi: 10.1016/j.csite.2022.102378.
• F. Oflaz, "Evaluation of the thermo-hydraulic behavior of water-based graphene and Al2O3 hybrid nanofluids in a circular tube through CFD simulations," Journal of Thermal Analysis and Calorimetry, pp. 1-16, 2025, doi: 10.1007/s10973-025-13993-4.
• A. Fattahi, "On the rotary concentrated solar collector containing twisted ribs and MgO-Ag-water nanofluid," Journal of the Taiwan Institute of Chemical Engineers, vol. 124, pp. 29-40, 2021, doi: 10.1016/j.jtice.2021.05.013
• M. Noorbakhsh, M. Zaboli, and S. S. Mousavi Ajarostaghi, "Numerical evaluation of the effect of using twisted tapes as turbulator with various geometries in both sides of a double-pipe heat exchanger," Journal of Thermal Analysis and Calorimetry, vol. 140, pp. 1341-1353, 2020, doi: 10.1007/s10973-019-08509-w
• M. Hazbehian, H. Maddah, H. Mohammadiun, and M. Alizadeh, "Experimental investigation of heat transfer augmentation inside double pipe heat exchanger equipped with reduced width twisted tapes inserts using polymeric nanofluid," Heat and Mass Transfer, vol. 52, no. 11, pp. 2515-2529, 2016, doi: 10.1007/s00231-016-1764-y.
• S. Paneliya, S. Khanna, V. Mankad, A. Ray, P. Prajapati, and I. Mukhopadhyay, "Comparative study of heat transfer characteristics of a tube equipped with X-shaped and twisted tape insert," Materials Today: Proceedings, vol. 28, pp. 1175-1180, 2020, doi: 10.1016/j.matpr.2020.01.103.
• M. E. Nakhchi and J. A. Esfahani, "Numerical investigation of different geometrical parameters of perforated conical rings on flow structure and heat transfer in heat exchangers," Applied Thermal Engineering, vol. 156, pp. 494-505, 2019, doi: 10.1016/j.applthermaleng.2019.04.067.
• H. Karakaya and A. Durmuş, "Heat transfer and exergy loss in conical spring turbulators," International Journal of Heat and Mass Transfer, vol. 60, pp. 756-762, 2013, doi: 10.1016/j.ijheatmasstransfer.2013.01.054.
• Inc ANSYS, "Ansys Fluent Theory Guide R17," vol. 2 Canonsburg, PA: ANSYS Inc., 2016.
• J. D. Anderson, "Governing equations of fluid dynamics," Computational fluid dynamics: an introduction, 2nd ed., J. F. Wendt, Ed. Berlin, Germany: Springer, 1992, pp. 15–51.
• R. L. Webb and N.-H. Kim, Principles of enhanced heat transfer, 2nd ed. New York, NY, USA: Garland Science/Taylor & Francis, 2004.
• S. Bahrehmand and A. Abbassi, "Heat transfer and performance analysis of nanofluid flow in helically coiled tube heat exchangers," Chemical Engineering Research and Design, vol. 109, pp. 628-637, 2016, doi: 10.1016/j.cherd.2016.03.022
• T. L. Bergman, A. S. Lavine, F. P. Incropera, and D. P. DeWitt, Fundamentals of Heat and Mass Transfer, 7th ed. Hoboken, NJ, USA: John Wiley & Sons, 2011.