Analysis of hydro-thermal and entropy generation characteristics of nanofluid in an aluminium foam heat sink by employing Darcy-Forchheimer-Brinkman model coupled with multiphase Eulerian model

Abstract

The efficiency and the operational life of the modern high-tech electronics are essentially dependent on their effective thermal management. The metal foam heat sinks cooled by nanofluid are the potential candidate for electronic cooling applications. Therefore, this study investigates the hydrothermal and entropy generation aspects of nanofluid in an aluminum foam heat sink. The multiphase Eulerian model couple with the Darcy-Forchheimer-Brinkman model was introduced to model nanofluid in the metal foam. The performance of nanofluid dependent on substrate porosity and nanoparticles is analyzed for porosity and Reynolds number ranges of 0.5–0.8 and 600–1800, respectively. The probed nanofluid sample consisted of a 0.5% volume fraction of aqueous-based alumina nanoparticles with 40 nm diameter. The hydrothermal results are evaluated in terms of average Nusselt number, local heat transfer coefficient, pumping power and performance evaluation criteria of the heat sink. Additionally, the fluid dynamics and surface temperature distribution across the heat sink are illustrated with velocity streamlines, velocity, and thermal contours. The entropy generation aspects are discussed in the form of thermal, viscous and total entropy parameters. The results demonstrate that the heat transfer enhancement of the nanofluid is optimized by increasing the substrate porosity at the expense of the least pressure drop. The effect of media permeability on the performance of the nanofluid is more evident at a larger Reynolds number. At the Reynolds number of 1800, utilization of the nanofluid resulted in the maximum Nusselt number enhancement of 5%, 15% and 33% for the foam porosities of 0.5, 0.7 and 0.8, respectively.