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THERMAL SCIENCE
International Scientific Journal
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NUMERICAL STUDY OF THE CONJUGATE MIXED CONVECTION IN INCLINED FINNED ANNULUS
ABSTRACT
The current study presents a numerical simulation of 3-D heat transfer by mixed convection between two inclined concentric cylinders. The outer cylinder undergoes internal volumetric heating, while the inner one remains adiabatic. The annulus is equipped with eight internal longitudinal fins attached to the outer cylinder. In this work, the effect of the annulus inclination angle on the fluid dynamics and heat transfer performance is investigated. The convection in the fluid region is associated with heat conduction in the solid wall thickness. The conservation equations are solved using the finite volume method with a second-order space-time discretization. The studied inclination angles are: 0°, 15°, 30°, 45°, 60°, 75°, and 90°, the Prandtl number is 8.082, while the Reynolds and Grashof numbers are 399.02 and 12801, respectively. The results showed that the axial Nusselt number increases with the decrease of the inclination angle, the dynamic and thermal fields become axisymmetric in the vertical annulus case. Moreover, the used fins at the bottom azimuthal position improved the heat transfer better than those at the upper. Finally, a correlation which quantifies the rate of heat transfer is added.
KEYWORDS
PAPER SUBMITTED: 2025-04-11
PAPER REVISED: 2025-08-02
PAPER ACCEPTED: 2025-08-05
PUBLISHED ONLINE: 2025-11-01
DOI REFERENCE: https://doi.org/10.2298/TSCI250411181B
CITATION EXPORT: view in browser or download as text file
REFERENCES
[1] Patankar, S. V., et al., Analysis of Turbulent Flow and Heat Transfer in Internally Finned Tubes and Annuli, Journal of Heat Transfer, 101 (1979), 1, pp. 29-37, 10.1115/1.3450925
[2] Dong, Z. F., et al., A numerical Analysis of Thermally Developing Flow in Elliptic Ducts with Internal Fins, International Journal of Heat and Fluid-Flow, 12 (1991), 2, pp. 166-172, 10.1016/0142-727x(91)90044-v
[3] Alam, I., et al., A Study of Heat Transfer Effectiveness of Circular Tubes with Internal Longitudinal Fins Having Tapered Lateral Profiles, International Journal of Heat and Mass Transfer, 45 (2002), 6, pp. 1371-1376, 10.1016/s0017-9310(01)00240-x
[4] Hassen, H., et al., Conjugate Heat Transfer in an Annulus with Heated Longitudinal and Transversal Fins, International Journal of Thermofluid Science and Technology, 10 (2023), 2, 100204, 10.36963/ijtst.2023100204
[5] Touahri, S., Boufendi, T., The 3-D-Computational Study of the Heat Transfer Enhancement by Using Longitudinal and Transversal Internal Fins in a Heated Horizontal Pipe, International Journal of Materials, Mechanics and Manufacturing, 4 (2015), 4, pp. 282-287, 10.18178/ijmmm.2016.4.4.272
[6] Hussein, A. K., Applications of Nanotechnology to Improve the Performance of Solar Collectors-Recent Advances and Overview, Renewable Energy Reviews, 62 (2016), Sept., pp. 767-792, 10.1016/j.rser.2016.04.050
[7] Gourari, S., et al., Numerical Study of Natural-Convection between Two Coaxial Inclined Cylinders, International Journal of Heat and Technology, 37 (2019), 3, pp. 779-786, 10.18280/ijht.370314
[8] Tayebi, T., et al., Effect of Internal Heat Generation or Absorption on Conjugate Thermal-Free Convection of a Suspension of Hybrid Nanofluid in A Partitioned Circular Annulus, International Communications in Heat and Mass Transfer, 126 (2021), 105397, 10.1016/j.icheatmasstransfer.2021.105397
[9] Touahri, S., Boufendi, T., Computational Study of the Effects of Heat Generating Finned Annular Pipe on the Conjugate Heat Transfer, in: Progress in Clean Energy, Springer, Cham, Switzerland, 2015, pp. 357-370, 10.1007/978-3-319-16709-1_25
[10] Elboughdiri, N., et al., Effects of Joule Heating and Viscous Dissipation on EMHD Boundary-Layer Rheology of Viscoelastic Fluid over an Inclined Plate, Case Studies in Thermal Engineering, 34 (2024), 104602, 10.1016/j.csite.2024.104602
[11] Touahri, S., Boufendi, T., Conjugate Heat Transfer with Variable Fluid Properties in a Heated Horizontal Annulus, Heat Transfer Research, 64 (2015), 11, pp. 1019-1038, 10.1615/heattransres.2015005019
[12] Touahri, S., et al., The Effect of Increasing the Thickness of an Annular Space Subjected to a Uniform Heat Flux on the Dynamic and Thermal Fields, in: Springer Proceedings in Materials, Springer Nature, Berlin, Germany, 2024, pp. 297-308, 10.1007/978-981-97-1916-7_31
[13] Benkhedda, M., et al., Laminar Mixed Convective Heat Transfer Enhancement by Using Ag-TiO2-Water Hybrid Nanofluid in a Heated Horizontal Annulus, Journal of Heat and Mass Transfer, 54 (2018), 1, pp. 2799-2814, 10.1007/s00231-018-2302-x
[14] Khemici, M., et al., Numerical Study of Developing Laminar Mixed Convection in a Heated Annular Duct with Temperature-Dependent Properties, Thermal Science, 23 (2019), 6A, pp. 3411-3423, 10.2298/tsci171013079k
[15] Touahri, S., et al., Numerical Study of the Conjugate Heat Transfer in a Horizontal Pipe Heated by Joulean Effect, Thermal Science, 16 (2012), 1, pp. 53-67, 10.2298/tsci101120080t
[16] Benzeggouta, O., et al., Comparative Study of Fluid-Flow and Heat Transfer Between Usual Fluids and Nanofluids in a Heated Horizontal Pipe, Journal of Thermal Science and Technology, 13 (2018), 2, 17-00366, 10.1299/jtst.2018jtst0027
[17] Redjaimia, I., et al., Numerical Approach of the First Instability Appearance in Inclined Taylor-Couette System, Journal of Thermophysics and Heat Transfer, 38 (2024), 4, pp. 1-10, 10.2514/1.t7065
[18] Boudellioua, R., et al., Numerical Analysis of Instabilities in Taylor-Couette Systems under Constant Heat Flux, Journal of Thermophysics and Heat Transfer, 39 (2025), 4, pp. 1000-1011, 10.2514/1.t7234
[19] Huq, M., et al., Experimental Measurements of Heat Transfer in an Internally Finned Tube, International Communications in Heat and Mass Transfer, 25 (1998), 5, pp. 619-630, 10.1016/s0735-1933(98)00049-9
[20] Yu, B., et al., Experimental Study on the Pressure Drop and Heat Transfer Characteristics of Tubes with Internal Wave-Like Longitudinal Fins, Heat and Mass Transfer, 35 (1999), 1, pp. 65-73, 10.1007/s002310050299
[21] Yan, W.-M., Sheen, P. J., Heat Transfer and Friction Characteristics of Fin-and-Tube Heat Exchangers, International Journal of Heat and Mass Transfer, 43 (2000), 9, pp. 1651-1659, 10.1016/s0017-9310(99)00229-x
[22] Zhou, Y., et al., Study on Heat Transfer Characteristics of the Whole Plate Fin Tube Cooler, International Journal of Thermofluid Science and Technology, 7 (2020), 2, 070204, 10.36963/ijtst.2020070204
[23] Benhacine, H., et al., Stability of Conducting Fluid-Flow between Coaxial Cylinders under Thermal Gradient and Axial Magnetic Field, International Journal of Thermofluid Science and Technology, 9 (2022), 2, 090202, 10.36963/ijtst.2022090202
[24] Zhang, M., et al., Experimental Investigation on Flow-Induced Vibrations of a Circular Cylinder with Radial and Longitudinal Fins, Journal of Wind Engineering and Industrial Aerodynamics, 223 (2022), 104948, 10.1016/j.jweia.2022.104948
[25] Liu, L., et al., Experimental and Numerical Investigation on the Flow and Heat Transfer Characteristics of the Tube with an Integrated Internal Longitudinal Fin, International Journal of Thermal Sciences, 183 (2023), 107857, 10.1016/j.ijthermalsci.2022.107857
[26] Mosaad, M., Conjugate Heat Transfer of Two Forced Convection Boundary-Layers in Counter Flow, Journal of Thermophysics and Heat Transfer, 31 (2017), 1, pp. 130-135, 10.2514/1.t4967
[27] Engblom, W., et al., Conjugate Conduction-Convection Heat Transfer for Water-Cooled High-Speed Flows, Proceedings, 46th AIAA Aerospace Sciences Meeting and Exhibit, Reno, Nev., USA, 2008, 32114, 10.2514/6.2008-4653
[28] Chen, C. K., Char, M. I., The effect of Prandtl Number pn Conjugate Heat Transfer from a Moving Circular Fiber, Proceedings, 23rd Thermophysics, Plasmadynamics and Lasers Conference, Houston, Tex., USA, 1988, 2939, 10.2514/6.1988-2639
[29] Sadeghi, M., et al., Gaseous Slip-Flow Mixed Convection through Ordered Microcylinders, Journal of Thermophysics and Heat Transfer, 28 (2014), 1, pp. 105-117, 10.2514/1.t4167
[30] Chidouah, W., Boufendi, T., Mixed Convection of Hybrid Nanofluid in Inclined Annulus Subjected to Solar radiation, Journal of Thermophysics and Heat Transfer, 36 (2022), 3, pp. 707-719, 10.2514/1.t6497
[31] Leong, J. C., Lai, F. C., Mixed Convection in a Rotating Concentric Annulus with a Porous Sleeve, Journal of Thermophysics and Heat Transfer, 33 (2019), 2, pp. 483-494, 10.2514/1.t5578
[32] Churchill, S. W., Chu, H. S., Correlating Equations for Laminar and Turbulent Free Convection from a Horizontal Cylinder, International Journal of Heat and Mass Transfer, 18 (1975), 9, pp. 1049-1053, 10.1016/0017-9310(75)90222-7
[33] Baehr, H. D., Stephan, K., Heat and Mass Transfer, Springer-Verlag, Berlin, Germany, 1998
[34] Patankar, S. V., Numerical Heat Transfer and Fluid-Flow, Hemisphere Pub. Co., McGraw-Hill, New York, USA, 1980, pp. 120-129
[35] Nonino, C., Giudice, S. D., Finite Element Analysis of Laminar Mixed Convection in the Entrance Region of Horizontal Annular Ducts, Numerical Heat Transfer - Part A: Applications, 29 (1996), 3, pp. 313-330, 10.1080/10407789608913795
[36] Nouar, C., Numerical Solution for Laminar Mixed Convection in a Horizontal Annular Duct: Temperature-Dependent Viscosity Effect, International Journal for Numerical Methods in Fluids, 29 (1999), 7, pp. 849-864, 10.1002/(sici)1097-0363(19990415)29:7<849::aid-fld820>3.0.co;2-f
[37] Islam, N., et al., Mixed Convection Heat Transfer in the Entrance Region of Horizontal Annuli, International Journal of Heat and Mass Transfer, 44 (2001), 11, pp. 2107-2120, 10.1016/s0017-9310(00)00223-4
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© 2026 Society of Thermal Engineers of Serbia. Published by the Vinča Institute of Nuclear Sciences, National Institute of the Republic of Serbia, Belgrade, Serbia. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International licence