Abstract
Metal manufacturing plants, nuclear power plants (which produce steam, by using thermal energy yielded during the nuclear fission, for spinning enormous turbines to generate electricity), and geothermal power plants are a few in the extensive list of technologies where different processes occur in high temperature environment in the presence of strong magnetic fields. Nanofluids (NFs), on the other hand, have been successful in achieving wide acceptance as the next generation coolant in the above mentioned industries as well as in the automobiles, heat exchangers, and steam boilers, owing to their remarkable thermal performance. These observations motivate the authors to explore the change in the movement and thermal behavior of nanofluid (being used as a coolant) under a strong Lorentz force. We have considered the flow (being driven by counter-moving lids) containing nanoparticles in a square cavity subject to magnetic source below. Single-phase model (based on the assumption that the solid nanoparticles together with host fluid are in thermal equilibrium, with the same velocity field) has been employed for mathematically modeling the nanofluid, whereas a pseudo-transient approach is approved to treat the governing equations numerically in the stream-vorticity form. Nanoparticle volume fraction (0.0 ≤ ϕ ≤ 0.2), Reynolds number (1 ≤ Re ≤ 300) and Magnetic parameter (0 ≤ Mn ≤ 1000) are the ranges considered for the governing parameters, considered in the present investigation. We have noted that the nanoparticle concentration and the Lorentz force do not influence the Nusselt number much at the upper wall of the cavity whereas a remarkable rise in the heat transfer is noted in the upward direction, along the right vertical wall. Further, by almost doubling the magnetic field intensity, as high as 40% reduction in the average Nusselt number along the left vertical wall has been noted, whereas the friction factor undergoes a nearly 60% increase along the lower horizontal wall. We have also noted the emergence of new vortices in the flow field, as a result of the imposition of the magnetic force. It is therefore recommended that special care must be taken, about the presence of external magnetic fields, where vortices negatively influence the performance of industrial processes.