Numerical study on thermal and concentration relaxation time in tri, hybrid and mono nano-Sutterby magnetohydrodynamic fluid under generalized diffusion conditions

Abstract

Sutterby fluid is a viscoelastic fluid and heat and mass transfer in such fluids obeys thermal and concentration memory effects which cannot be analyzed through classical laws of heat conduction and mass diffusion. This is the main motivation toward this study. Therefore, this article considers viscoelastic effects in the presence of thermal and solutal memory effects. A novel theory of heat and mass is simultaneously implemented and generalized models are developed because classical energy and heat equations do not provide accurate information for fluids with memory effect. These generalized models are reducible to their classical cases. Hence, this study considers both generalized and classical aspects. Further, generalized models are solved numerically with the help of the FEM. Results are computed for quantities of engineering interest. The predictions perceived from the analysis are of the use of engineers and industry to design nanofluids with desired thermal properties. A destructive chemical reaction in mono-nanofluid has the highest decreasing effect (relative to tri- and hybrid nanofluids) on the concentration field. A moderate effect of destructive chemical reaction on concentration field in hybrid nanofluid is seen. Mono, hybrid, and tri-nanofluids perceived different magnetic effects. Hybrid nanofluid experiences the greatest magnetic force in comparison with mono and tri-nanofluids. It is seen from the simulations that tri-nanofluid generates the highest heat as a result of Ohmic dissipation. Thus, in comparison with mono and hybrid nanofluid tri-nanofluid offers the highest resistance to the flow of electric current. Moreover, tri-nanoparticles are responsible for an optimized increase in thermal conductivity of Sutterby fluid relative to mono and hybrid nanoparticles. Thus, tri-nanofluid may serve as better coolant, a medium for transporting heat. Destructive chemical reaction in mono-nanofluid has the highest decreasing effect on the concentration field. A moderate effect of destructive chemical reaction on concentration field in hybrid nanofluid is seen. Tri-nanofluid exerts the highest shear stress on the solid boundary while the least shear stress on the wall is seen in the case of mono-nanofluid. A 56% increase in the Nusselt number is noticed if hybrid nanoparticles disperse rather than mono nanoparticles. Similarly, a 59% increase in the Nusselt number is observed if tri-nanoparticles are dispersed rather than mono nanoparticles. Thus the significant rise in heat transfer is possible due to the dispersion of tri-nanoparticles.