In this paper, a 2D numerical study of natural convection heat transfer in a W-shaped inclined enclosure with a variable aspect ratio was performed. The enclosure contained a porous medium saturated with Ag/Al₂O₃ hybrid nanofluid in the presence of uniform heat generation or absorption under the effect of a uniform magnetic field. The vertical walls of the enclosure were heated differentially; however, the top and bottom walls were kept insulated. The governing equations were solved with numerical simulation software COMSOL Multiphysics which is based on the finite element method. The results showed that the convection heat transfer was improved with the increase of the aspect ratio; the average Nusselt number reached a maximum for an aspect ratio (AR) = 0.7 and the effect of the inclination was practically negligible for an aspect ratio of AR = 0.7. The maximum heat transfer performance was obtained for an inclination of $\omega =15$ and the minimum is obtained for $\omega =30$ . The addition of composite nanoparticles ameliorated the convection heat transfer performance. This effect was proportional to the increase of Rayleigh and Darcy numbers, the aspect ratio and the fraction of Ag in the volumetric fraction of nanoparticles.

Cooling electronic devices using heat sinks is one of the main fields in which academics are working to develop them. This manuscript presents a novel numerical study using Comsol Multiphysics to optimize heat sink performance through the strategic integration of magnetohydrodynamic (MHD) radiative nanofluid and innovative helical trapezoidal wings on cylindrical fins. The research advances the field by systematically replacing classical cylindrical fins with those provided with cylindrical wings as a first step, and with trapezoidal shapes as a second step and subsequently introducing helical trapezoidal wings instead of the aligned shape to enhance efficiency. Comsol Multiphysics 3.4 software is used to conduct the study applying finite element method. The 2D heat sink problem is modelled as a square cavity, which is equipped with 2D longitudinal section of cylindrical fins and filled with MHD radiative nanofluid. The study examined the impact of using cylindrical wings attached laterally on the cylindrical fins. Then, the efficiency of cylindrical wings is compared with trapezoidal shape. Finally, the helical trapezoidal wings are used to enhance the heat sink efficiency. The findings reveal substantial performance improvements: with nanofluid by 42.83%, enhancement with radiation by 54.19%, with cylindrical wings by 22.38%, and a superior 10.7% efficiency increase with trapezoidal wings. In addition, using helical trapezoidal wings is the optimum for the heat sink performance by 7.26%. This work is poised to appeal to a broad readership by offering valuable insights into optimizing heat sink configurations for enhanced thermal management.

Enhancing the thermal efficiency of pin fin heat sinks is a key concern in engineering, especially for managing heat in electronic components. Performance is heavily influenced by factors such as fin geometry, spacing, orientation, fluid flow behavior, and available heat transfer surface area. This study explores the combined effects of porous media, graphene (carbon-based nanoparticles)-water radiative nanofluids, and externally mounted V-shaped ribs on the natural convection performance of pin fin heat sinks. The combined influence of radiative nanofluid flow, V-shaped ribbed pin fins, and porous medium permeability on natural convection heat sink efficiency has never been examined in a single study. The enhancement strategy starts with modifying Classic Pin Fins (CPF) by incorporating standard transverse ribs, resulting in a configuration referred to as Pin Fins with Classic Ribs. For further thermal improvement, these ribs are substituted with V-shaped ribs to get Pin Fins with V-shaped Ribs (PFVSR), and the impact of varying the opening angle ( γ ) is analyzed to determine optimal conditions. To intensify heat removal, the entire heat sink system is embedded in a porous domain saturated with a radiatively active graphene-based nanofluid. Numerical simulations are performed in COMSOL Multiphysics to assess the roles of several key parameters. Because of increased buoyancy driven flow and better nanofluid circulation, numerical simulations show that the PFVSR configuration increases the average Nusselt number by 16.21% when compared to the CPF model. Heat transfer is further improved by 4% when the rib opening angle is optimized. The average Nusselt number rises by 45.86% when the heat sink is embedded in a high-permeability porous medium (Da = 10 2 ) as opposed to the low permeability instance (Da = 10 − 4 ), demonstrating the crucial role permeability plays in natural convection augmentation. Moreover, adding thermal radiation ( R d = 1) speeds up the flow field and boosts heat transfer efficiency by 15.84%. These findings show that a high-performance, compact heat sink design can be achieved by the combination of geometric alteration, porous media, radiative effects, and nanofluids.