Research Article

A Novel Passive Thermal Diode Based on Natural Convection Using an Internal Baffle and a One-Way Valve: A Numerical Investigation

Authors

Mostafa Rahimi * Department of Mechanical Engineering, University of Mohaghegh Ardabili, Ardabil, Iran.
Arezoo Sadat Bathaei Department of Mechanical Engineering, University of Mohaghegh Ardabili, Ardabil, Iran.

https://doi.org/10.48313/mtei.v3i1.80

Downloads

Abstract

The present paper deals with a detailed numerical analysis of natural convective heat transfer in a rectangular enclosure subjected to heating from one side. The analysis is done independently for two different fluids: water (Pr = 7) and air (Pr = 0.7) by considering the Rayleigh number variation between 10³ and 4×10⁵ to cover both asymptotic and early laminar convection regimes. The solution of the governing equations (continuity, momentum, and energy) is obtained using a finite difference scheme with the Boussinesq approximation in MATLAB. The validation of the numerical method is successfully carried out with the help of benchmark solutions of De Vahl Davis and highly accurate solutions of Wan et al. After that, an obstacle (baffle) of small thickness is fixed at the mid-height of the cavity without hindering the flow, and the effect of the same on the overall heat transfer rate is analyzed. Finally, a low-density flap is attached to the upper edge of the obstacle to allow one-directional flow. Such a configuration allows designing a one-way thermal insulator; convective heat flow can be easily allowed from one side, while it is efficiently restricted from the opposite side when the valve is shut. These findings suggest that the presence of the baffle alone has no significant impact on the heat transfer process, which is reduced only by 2% for air and 0.2% for water due to the use of the baffle alone. In comparison, the heat transfer process is decreased by up to 95% for air and 92% for water with the help of the baffle-valve system.

Keywords

Natural convection Rectangular enclosure One-way heat transfer Baffle Thermal insulation Numerical simulation

References (21)

[1] Ostrach, S. (1972). Natural convection in enclosures. Journal of heat transfer, 8, 161–227. https://doi.org/10.1016/S0065-2717(08)70039-X

[2] Incropera, F. P., DeWitt, D. P., Bergman, T. L., Lavine, A. S. (1990). Fundamentals of heat and mass transfer. Wiley, New York. https://pdfyl.ertongbook.com/46/32527305.pdf

[3] Saitoh, T., & Hirose, K. (1989). High-accuracy benchmark solutions to natural convection in a square cavity. Computational mechanics, 4(6), 417–427. https://doi.org/10.1007/BF00293047

[4] De Vahl Davis, G. (1983). Natural convection of air in a square cavity: A benchmark numerical solution. International journal for numerical methods in fluids, 3(3), 249–264. https://doi.org/10.1002/fld.1650030305

[5] Nithyadevi, N., Kandaswamy, P., & Lee, J. (2007). Natural convection in a rectangular cavity with partially active side walls. International journal of heat and mass transfer, 50(23), 4688–4697. https://doi.org/10.1016/j.ijheatmasstransfer.2007.03.050

[6] Raji, A., Hasnaoui, M., Naïmi, M., Slimani, K., & Ouazzani, M. T. (2012). Effect of the subdivision of an obstacle on the natural convection heat transfer in a square cavity. Computers & fluids, 68, 1–15. https://doi.org/10.1016/j.compfluid.2012.07.014

[7] Bouafia, M., & Daube, O. (2007). Natural convection for large temperature gradients around a square solid body within a rectangular cavity. International journal of heat and mass transfer, 50(17), 3599–3615. https://doi.org/10.1016/j.ijheatmasstransfer.2006.05.013

[8] da Silva, A. K., & Gosselin, L. (2005). On the thermal performance of an internally finned three-dimensional cubic enclosure in natural convection. International journal of thermal sciences, 44(6), 540–546. https://doi.org/10.1016/j.ijthermalsci.2004.11.011

[9] Zhang, Z., Bejan, A., & Lage, J. L. (1991). Natural convection in a vertical enclosure with internal permeable screen. Journal of heat transfer, 113(2), 377–383. https://doi.org/10.1115/1.2910572

[10] Laguerre, O., Benamara, S., Remy, D., & Flick, D. (2009). Experimental and numerical study of heat and moisture transfers by natural convection in a cavity filled with solid obstacles. International journal of heat and mass transfer, 52(25), 5691–5700. https://doi.org/10.1016/j.ijheatmasstransfer.2009.07.028

[11] Gebhart, B., Jaluria, Y., Mahajan, R. L., Sammakia, B., & Yovanovich, M. M. (1989). Buoyancy-induced flows and transport. Journal of electronic packaging, 111(4), 321. https://doi.org/10.1115/1.3226555

[12] C. Wan, B. S. V. Patnaik, G. W. W. D. (2001). A new benchmark quality solution for the buoyancy-driven cavity by discrete singular convolution. Numerical heat transfer: Part B: Fundamentals, 40(3), 199–228. https://doi.org/10.1080/104077901752379620

[13] Bawazeer, S. A., & Alsoufi, M. S. (2025). Natural convection in a square cavity: Effects of Rayleigh and Prandtl numbers on heat transfer and flow patterns. Case studies in thermal engineering, 73, 106680. https://doi.org/10.1016/j.csite.2025.106680

[14] Bejan, A. (2013). Convection heat transfer. John wiley & sons. https://www.amazon.com/s?k=9780470900376&i=stripbooks&linkCode=qs

[15] Hussein, A. K., Ghodbane, M., Said, Z., & Ward, R. S. (2022). The effect of the baffle length on the natural convection in an enclosure filled with different nanofluids. Journal of thermal analysis and calorimetry, 147(1), 791–813. https://doi.org/10.1007/s10973-020-10300-1

[16] Barman, P., & Rao, P. S. (2021). Natural convection inside a heat source-embedded wavy porous cavity containing an insulated obstacle. Proceedings of the institution of mechanical engineers, part e: Journal of process mechanical engineering, 235(5), 1694–1704. https://doi.org/10.1177/09544089211016212

[17] Rachedi, K., Ragueb, H., Behnous, D., Tahiri, A., Manser, B., & Chikh, M. A. A. (2026). Analysis of natural convection heat transfer in a rectangular cavity with discrete heat flux: Implications for building thermal management using artificial neural networks. Numerical heat transfer, part b: Fundamentals, 87(1), 2389215. https://doi.org/10.1080/10407790.2024.2389215

[18] El Hamri, A., Mahdoui, M., Bahraoui, F., Chesneau, X., & Zeghmati, B. (2024). Entropy generation and natural convection in a square cavity with a horizontal partition and a heated square block. Advances in thermal science and energy (pp. 249–259). Cham: Springer Nature Switzerland. https://doi.org/10.1007/978-3-031-43934-6_26

[19] Idan, S., & Feldman, Y. (2017). “Smart” passive thermal insulation of confined natural convection heat transfer: An application to hollow construction blocks. Applied thermal engineering, 124, 1328–1342. https://doi.org/10.1016/j.applthermaleng.2017.06.021

[20] Trefethen, L. M., & Chung, K. C. (1978). The one-way heat wall: Analysis and experiments on a vertical stack of inclined cavities. International heat transfer conference digital library. Begel House Inc. https://www.dl.begellhouse.com/references/2d9b67ad1b92ab15,4242f01c32efeded,569357fd5dd0ccde.html

[21] Nazari, M., & Ramezani, S. (2011). Natural convection in a square cavity with a heated obstacle using the lattice Boltzmann method. Modares mechanical engineering, 11(9), 119-133. (In Persian). https://dor.isc.ac/dor/20.1001.1.10275940.1390.11.2.14.4

Article Metrics

Published 2026-03-19
Issue Vol. 3 No. 1 (2026): Mechanical Technology and Engineering Insights (MTEI)
Section Articles
Document Type Research Article
Views 0
Downloads 0

How to Cite

Rahimi, M. ., & Bathaei, A. S. . (2026). A Novel Passive Thermal Diode Based on Natural Convection Using an Internal Baffle and a One-Way Valve: A Numerical Investigation. Mechanical Technology and Engineering Insights, 3(1), 56-68. https://doi.org/10.48313/mtei.v3i1.80

Download Citation

Similar Articles

Victoria Nozick, Omar Mar Cornelio, Mixed Convection in A Square Cavity with Heat-Generating Conducting Body , Mechanical Technology and Engineering Insights: Vol. 2 No. 2 (2025): Mechanical Technology and Engineering Insights (MTEI)
Hassan Masoomi, Delara Daneshvar, Lattice Boltzmann Simulation of Heat Transfer in a Square Cavity Coupled with Copper–Graphene Nanocomposite Wall , Mechanical Technology and Engineering Insights: Vol. 2 No. 4 (2025): Mechanical Technology and Engineering Insights (MTEI)
Hamed Mohaddes Deylami, Effect of Fin Geometry on Natural Convection in a Rotated Rectangular Enclosure , Mechanical Technology and Engineering Insights: Vol. 2 No. 4 (2025): Mechanical Technology and Engineering Insights (MTEI)
Khadijeh Ghaziani, Omar Mar Cornelio, Influence of Optical Thickness and Inclination Angle on Coupled Natural Convection and Thermal Radiation in Inclined Cavities , Mechanical Technology and Engineering Insights: Vol. 1 No. 4 (2024): Mechanical Technology and Engineering Insights (MTEI)
Hashem Saberi Najafi, Jafar Biazar, Homotopy Analysis Method (HAM) of Nanofluid Natural Convection over a Cone in Porous Media for Nuclear Waste , Mechanical Technology and Engineering Insights: Vol. 1 No. 4 (2024): Mechanical Technology and Engineering Insights (MTEI)
Khadijeh Ghaziyani, Mehdi Moslemi, Numerical Analysis of Combined Heat and Mass Transfer by Mixed Convection over a Vertical Wall , Mechanical Technology and Engineering Insights: Vol. 2 No. 3 (2025): Mechanical Technology and Engineering Insights (MTEI)
Seyed Ahmad Edalatpanah, Hashem Saberi Najafi, Numerical Investigation of Natural Convection Heat Transfer in Turbulent Flow Inside a Square Enclosure Using Large Eddy Simulation , Mechanical Technology and Engineering Insights: Vol. 2 No. 2 (2025): Mechanical Technology and Engineering Insights (MTEI)
Seyed Ali Noorkhah, Natalja Osintsev, Free Convection of Herschel – Bulkley Fluids WithMHD Effect on a Vertical Moving Plate in Porous Media , Mechanical Technology and Engineering Insights: Vol. 2 No. 3 (2025): Mechanical Technology and Engineering Insights (MTEI)
Hossein Shokouhmand, Zeinab Montazerinejad, Numerical Investigation of the Effect of Pitch Variation on the Flow Field, Pressure Distribution, and Heat Transfer Coefficient in a Vertical Double-Pipe Helical Heat Exchanger , Mechanical Technology and Engineering Insights: Vol. 3 No. 2 (2026): Mechanical Technology and Engineering Insights (MTEI)
Hamed Mohaddes Deylami, Mohammad Kazem Hassanzadeh-Aghdam, Numerical Investigation of the Effect of Discrete Ribs on Flow Field and Heat Transfer in a Rectangular Channel , Mechanical Technology and Engineering Insights: Vol. 2 No. 3 (2025): Mechanical Technology and Engineering Insights (MTEI)

1-10 of 63 Next

You may also start an advanced similarity search for this article.