Numerical optimization of thermal performance in V-shaped ribbed pin-fin heat sinks using porous media filled with radiative nanofluid

Abstract

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 ( $\gamma$ ) 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.