Effect of uniform/non-uniform magnetic field and jet impingement on the hydrodynamic and heat transfer performance of nanofluids

Effect of uniform and non-uniform magnetic field and jet impingement on the hydrodynamic and heat transfer performance of nanofluids has been investigated numerically. Five types of magnetic field with different strengths (Ha = 0-40) are applied externally to the flow domain under direct and transverse jet (cross-flow) impingement conditions. The effect of Reynolds number (Re = 200-600), nanoparticle type (Cu, Al, TiO2, and hybrid (Cu + TiO2)), nanoparticle diameter (d(p) = 20 nm-80 nm) and concentration (empty set = 1 vol% to 3 vol%) on the hydrodynamic and heat transfer behavior under uniform and non-uniform magnetic field are predicted. The presence of magnetic field introduced a Lorentz force responsible for higher values of flow velocity particularly near the walls resulting in the enhancement of average Nusselt number. Moreover, the direct and transverse jet against the applied uniform/non-uniform magnetic field also enhanced the local flow velocity near the impingement region leading to enhancement in the local Nusselt number. Transverse jet exhibits higher average Nusselt number in comparison with direct jet. A maximum heat transfer enhancement of 173% is obtained for 3 vol% Cu nanofluid under magnetic field. Moreover, two equivalent nanofluid pairs are also identified that will provide a better switching option in thermal management of high power electronic devices and nuclear reactors.