Free convection heat transfer of MgO-MWCNTs/EG hybrid nanofluid in a porous complex shaped cavity with MHD and thermal radiation effects

Abstract

Purpose The present study aims to address the flow and heat transfer of MgO-MWCNTs/EG hybrid nanofluid in a complex shape enclosure filled with a porous medium. The enclosure is subject to a uniform inclined magnetic field and radiation effects. The effect of the presence of a variable magnetic field on the natural convection heat transfer of hybrid nanofluids in a complex shape cavity is studied for the first time. The geometry of the cavity is an annular space with an isothermal wavy outer cold wall. Two types of the porous medium, glass ball and aluminum metal foam, are adopted for the porous space. The governing equations for mass, momentum and heat transfer of the hybrid nanofluid are introduced and transformed into non-dimensional form. The actual available thermal conductivity and dynamic viscosity data for the hybrid nanofluid are directly used for thermophysical properties of the hybrid nanofluid. Design/methodology/approach The governing equations for mass, momentum and heat transfer of hybrid nanofluid are introduced and transformed into non-dimensional form. The thermal conductivity and dynamic viscosity of the nanofluid are directly used from the experimental results available in the literature. The finite element method is used to solve the governing equations. Grid check procedure and validations were performed. Findings The effect of Hartmann number, Rayleigh number, Darcy number, the shape of the cavity and the type of porous medium on the thermal performance of the cavity are studied. The outcomes show that using the composite nanoparticles boosts the convective heat transfer. However, the rise of the volume fraction of nanoparticles would reduce the overall enhancement. Considering a convective dominant regime of natural convection flow with Rayleigh number of 107, the maximum enhancement ratio (Nusselt number ratio compared to the pure fluid) for the case of glass ball is about 1.17 and for the case of aluminum metal foam is about 1.15 when the volume fraction of hybrid nanoparticles is minimum as 0.2 per cent. Originality/value The effect of the presence of a variable magnetic field on the natural convection heat transfer of a new type of hybrid nanofluids, MgO-MWCNTs/EG, in a complex shape cavity is studied for the first time. The results of this paper are new and original with many practical applications of hybrid nanofluids in the modern industry.

Hydrodynamic and thermal analysis of water, ethylene glycol and water-ethylene glycol as base fluids dispersed by aluminum oxide nano-sized solid particles

“…They studied the effects of the Rayleigh number, fin length, oscillating amplitude, oscillating period, thermal conductivity ratio (fin to fluid) and the non-dimensional Young's modulus. Other research studies can be found in literature (Ghalambaz and Noghrehabadi, 2014; Ghalambaz et al , 2014a, 2014b, 2019; Noghrehabadi et al , 2012a, 2012b, 2012c, 2013a, 2013b, 2014; Mansour et al , 2016; Ahmed et al , 2013; EL-Kabeir et al , 2007; Rashad, 2008; Rashad et al , 2011, 2017a, 2017b; Gorla et al , 2011; Sivasankaran et al , 2016; Liu et al , 2019; Aly and Pop, 2019; Nasrin et al , 2019; Sreedevi et al , 2019; Hayat et al , 2015; Mohammed et al , 2012; Makinde (2013); Şenay et al , 2019; Prakash and Agrawal, 2016; Rajesh et al , 2017; Khamis et al , 2015; Alsabery et al , 2019; Vemula et al , 2016; Fornalik-Wajs et al , 2019; Sun and Pop, 2014; Malvandi et al , 2017; Thumma et al , 2017; Rawat et al , 2019; Venkateswarlu et al , 2019a, 2019b). In these research works, different nanofluid parameters and various numerical and experimental models were addressed.…”

Mixed Convection of Hybrid Nanofluid in an Inclined Enclosure with a Circular Center Heater under Inclined Magnetic Field

“…where φ hnf (= φ Ag + φ MgO ) is the volume fraction of hybrid nanoparticles. For effective electrical conductivity, the modified Maxwell model for hybrid nanofluids used by Ghalambaz, Sabour, Pop, and Wen [45] is assumed here and is stated as , 0 ≤ φ hn f ≤ 0.03 ( 9)…”

MHD Marangoni boundary layer problem for hybrid nanofluids with thermal radiation

“…More applications of nanofluids were presented in the important researches by Shenoy et al (2017), Chamkha et al (2018), Ahmed et al (2019) and Khan et al (2020). Further, effects of various physical fields and parameters on Carreau and Jeffrey nanofluids have been investigated in the research of Waqas et al (2019a, 2019b), respectively, in the presence of Hafnium and metallic nanoparticles over an inclined plane by Zeeshan et al (2019), for nano-encapsulated phase change materials in a cavity by Ghalambaz et al (2019a, 2019b) and of Cattaneo–Christov heat flux model towards stretching cylinder by Alamri et al (2019). In addition, mathematical and computational frameworks for different types of fluids can be found in Sheikholeslami et al (2019) and Waqas (2020).…”