Abstract In this study we analyzed the natural convection heat transfer in a rectangular enclosure containing circular cavities, which is important for the analysis of electronic cooling systems, heat exchangers, and energy storage units. To increase the thermal conductivity, copper nanofluid has been used to analyse its impact in comparison to conventional base fluids. The core intention is to explore the effects of major physical parameters such as Rayleigh number, volume fraction, flow dynamics, and heat transfer characteristics within the enclosure. The governing equations for mass, momentum, and energy conservation are formulated under the Boussinesq approximation, and COMSOL software has been used to solve the resulting equations by using the Galerkin finite element method with an upwind scheme to stabilize convective terms and ensure the accuracy. The results show that nanofluids greatly improve convective heat transfer compared to base fluids. The highest heat transfer happens near the cavities. Results indicate that increasing the nanoparticle volume fraction enhances the overall Nusselt number, which results in greater heat transfer. A 5 % volume fraction of nanoparticles leads to a 28 % increase in the Nusselt number as compared to pure water. Furthermore, heat transfer becomes more prominent near the cavity boundaries, where thermal gradients and flow interactions are more intense. These findings offer helpful suggestions for optimizing the design of thermal management systems across various engineering applications, including electronic devices, cooling, solar collectors, and industrial heat exchangers.
Faraz et al. (Thu,) studied this question.