Heat Transport in a Vertical Rectangular Conduit with Viscous Dissipation: Silver/Magnesium Oxide-Water Hybrid Nanofluid

Modern thermal duct systems are increasingly deploying nanofluids to achieve enhanced thermal efficiency in a range of technologies including nuclear power, process mechanical engineering and petro-chemical production. Motivated by these developments, the current study examines the buoyancy-driven convective transport of silver/magnesium oxide-water hybrid nanofluid (HNF) through a rigid vertical rectangular heated duct. The upper and lower boundaries of the duct are insulated, and the other walls are heated isothermally. Viscous heating effects are included. The transformed non-dimensional nonlinear boundary value problem derived is solved using in-house code. Verification of the accuracy of the FDM code is included via benchmarking with previous studies for special cases. A mesh independence test is also performed. For both cases of unitary nanofluid (NF) (deploying either magnesium oxide or silver nanoparticles) and HNF, temperature and velocity contour plots are provided for the impact of Grashof number, Brinkman number, nanoparticle solid volume fraction, and aspect ratio. The findings demonstrate that the velocity increases as the Grashof and Brinkman numbers increased, and that elevation in volume fraction exert a opposite result. For both unitary NF and HNF, the heat transfer rate falls at the right wall and rises at the left wall with a boost in values of Grashof number, Brinkman number, solid volume percentage, and aspect ratio.