Rashid, Farhan LaftaAl-Obaidi, Mudhar A.Alkhekany, Zainab Abdul KarimAhmad, ShabbirChibani, AtefAgyekum, Ephraim BonahJunjua, Moin Ud Din2025-09-152025-09-1520251388-61501588-292610.1007/s10973-025-14659-x2-s2.0-105014822749https://doi.org/10.1007/s10973-025-14659-xhttps://hdl.handle.net/20.500.14517/8357This review evaluates the effects of natural convection in square cavities using both mono-and hybrid Nano-fluids, focusing on the thermal management limitations of conventional fluids. The review highlights that there is a need for improved thermal solutions in engineering since regular fluids fail under low Rayleigh number conditions. Particularly, it shows that nano-fluids can increase significantly the rate of heat transfer with the Nusselt (Nu) number increasing as high as 60% compared to pure fluids, depending on nano-particle concentration, particle size, and material properties. For instance, the introduction of 4% Al<inf>2</inf>O<inf>3</inf> nano-particles into a water-based solution can increase the average Nusselt number from 7.5 to around 12.0 under corresponding conditions of heating. Moreover, hybrid nano-fluids possess excellent opportunities as efficient heat transfer promoters with over 30% improvement in efficiency rates. This kind of assessment indicates the revolutionary impact of nano-fluids on thermal applications, but more work is needed to explore their behavior when considering various ranges of temperatures and flow rates in order to develop trustworthy predictive models. © 2025 Elsevier B.V., All rights reserved.eninfo:eu-repo/semantics/closedAccessComputational Fluid Dynamics (CFD)Heat Transfer EnhancementHybrid Nano-FluidsNano-FluidsNatural ConvectionSquare Cavity FlowArticleQ2Q1