Quantification of free convection within a hemispherical annulus through a porous medium saturated by water-copper nanofluid

Abstract

Purpose A porous medium saturated with a nanofluid based on pure water and copper nanoparticles is used for cooling a hemispherical electronic device contained in an annulus space. The disc of the cavity could be inclined at an angle ranging from 0 ° (horizontal disc with dome facing upwards) to 180° (horizontal disc with dome facing downwards). The important surface heat flux generated by the dome leads to high Rayleigh number values reaching 7.29 × 10^10. The purpose of this work is to examine the influence of the nanofluid saturated porous medium on the free convective heat transfer. Design/methodology/approach Heat transfer occurring between this active component and the isothermal passive cupola is quantified by means of a three-dimensional numerical study using the control volume method associated to the SIMPLE algorithm. Findings The work shows that heat transfer in the annulus space is improved by interposing a porous medium saturated with the water-copper nanofluid. Originality/value New correlation is proposed to calculate the Nusselt number for any combination of the inclination angle, the fraction volume, the Rayleigh number and the ratio between the thermal conductivities of the porous medium and the fluid. The wide ranges corresponding to these parameters allow the thermal design of this electronic equipment for various configurations.

Role of curved walls on efficient thermal convection in porous beds confined within enclosures: heatline and entropy production maps

“…Experimental studies on thermal convection had been carried out in porous bed within various shapes of enclosures, such as fixed bed (Zhang and You, 2011), square cross section duct (Tian et al, 2018) and trapezoidal solar air heaters (Salih et al, 2021) to name a few. Numerical investigations on convection in porous bed within various shapes of enclosures involve hemispherical enclosure (Bairi et al, 2019a(Bairi et al, , 2019b, annulus between circular or square cylinders (Moukalled et al, 2016), porous fins involving various cross sections (rectangular, convex, concave and parabolic) (Kundu et al, 2012;Shateri and Salahshour, 2018), tilted cavity (Alchaar et al, 1995), cavities with various shapes (square, triangle, rhombus and cavities with convex or concave walls) (Biswal and Basak, 2016;Das et al, 2016Das et al, , 2018Das et al, , 2019Lukose and Basak, 2020) and wavy cavities (Rao and Barman, 2021;Cheong et al, 2017Cheong et al, , 2018. Steady convection within porous bed confined in various enclosures is induced via various wall heating.…”

Multiple-relaxation-time lattice Boltzmann model for simulation of free convection in axisymmetric nanofluid-filled annulus-experimental and numerical observations

“…In the recent years, several numerical and experimental investigations on free convection phenomenon have been conducted. It is due to wide range of applications of natural convection in the industrial applications such as solar collector, ventilation, thermal storage, meteorology science, nuclear reactors and so on (Purusothaman et al , 2019; Rahimi et al , 2019; Purusothaman and Malekshah, 2019; Baïri et al , 2019; Purusothaman et al , 2016a, 2016b; Purusothaman, 2018).…”