Finite element method for natural convection flow of Casson hybrid (Al2O3–Cu/water) nanofluid inside H-shaped enclosure

Abstract

The fundamental problem in electronic cooling systems is the implementation of a cavity such that it can be used to provide localized cooling to specific components, such as CPUs or GPUs, enhancing their performance and longevity. It can also be used in microfluidic devices for controlled drug delivery, where precise control of fluid flow is crucial. The present article numerically explores the free convection non-Newtonian Casson hybrid nanofluid phenomena that occur within an H-shaped cavity while heated from the middle. The heating efficiency and heat flow in a cavity are influenced by perpendicular hot walls that connect two vertical closed channels. A numerical solution is obtained by implementing the Galerkin finite element method to solve the partial differential equation. The numerical outcomes are depicted on the contour of streamlines and isotherms for different parameters in the following ranges: 0.1 ≤ η ≤ 0.4, 0.005≤ϕhp≤0.020, 0.1 ≤ γ ≤ 2, and 103 ≤ Ra ≤ 106 at fixed Pr = 6.2. In addition, line graphs show rate of heat transfer within the enclosure using the average Nusselt number for these parameters. Increased aspect ratios (η = 0.4) result in a minimal rate of heat transfer enhancement, whereas decreasing η leads to a significantly higher average Nusselt number and maximum heat transfer within the cavity. The convective rate of heat transfer increases with the presence of hybrid nanoparticles inside an H-shaped cavity for all Rayleigh numbers. The rotation of the Casson hybrid nanofluid also rises as the volume ratio of nanoparticles increases. For a fixed aspect ratio (A.R) of 0.1, the heat dissipation is 6.91% at a lower ϕhp value of 0.005 at a fixed Ra value of 105. However, it increases to 7.072% for a higher ϕhp value of 0.02 at Ra = 105. With increasing Ra number, ϕhp, and γ, the number NuAve increases.