Conjugate heat transfer of aqueous hybrid nanoliquid between coaxial cylinders subjected to magnetic field

Abstract

The current numerical investigation deals with the conjugate (conduction–convection) magnetohydrodynamic (MHD) incompressible flow and thermal dissipation processes of Multi-wall carbon nanotube - silver (MWCNT - Ag) water hybrid Newtonian nanoliquid filled in an annular enclosure. The inner cylinder having finite thickness is subjected to uniform/non-uniform thermal profiles whereas the exterior cylinder is kept at low temperature. However, the horizontal surfaces are retained adiabatic. An in-house FORTRAN code has been developed to solve the two dimensional, axisymmetric and unsteady governing equations by employing time-splitting technique. Detailed numerical simulations have been carried out for control parameters such as Rayleigh number, thermal conductivity ratio, wall thickness, Hartmann number, nanoparticle concentration and for a clear visualization of the impact of various range of these parameters, the obtained numerical results are represented by the streamlines, isotherms and plot of average Nusselt number values. From detailed numerical computations, greater heat transport rate is achieved with minimum wall thickness and maximum thermal conductivity ratio irrespective of thermal boundary condition. The results also reveal that hybrid nanoliquid with equal proportion of MWCNT and silver (Ag) nanoparticles dispersed in the water helps in dissipating maximum amount of thermal energy from the solid–fluid interface of annulus. In addition, uniform heating condition helps in extracting greater amount of heat dissipation compared to linear heating.

Keywords

• Annulus
• Conjugate
• Hybrid nanoliquid
• Magnetic field
• Linear and uniform thermal profile