ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING, vol.48, pp.11591-11620, 2023 (SCI-Expanded)
The current study
numerically explored the hydrothermal flow and entropy generation properties of
ferrofluid (water and Fe3O4) on a cylindrical body in the
rectangular channel subjected to the non-uniform magnetic field going through
current carrying wires. The effect of various
parameters, such as ferrofluid volume fraction, Φ the strength of the non-uniform
magnetic field, Ha, and Reynolds number, Re on the flow characteristics,
and forced convection heat transfer is investigated using finite-volume based
Ansys Fluent 20. Obtained results demonstrate that the applied magnetic
field shortens the length of recirculating wake downstream of the cylinder at Re=25
and makes unsteady flow with alternate vortex shedding as time-independent
steady flow for Hartmann numbers greater than, Ha≥6 at Re=100. At
Re=50, the total drag coefficient, CD gets higher by
almost 20% when Ha increases from Ha=0 to Ha=6 and
subsequently grows by 61% at Ha=10. The findings
show that the average Nusselt number, Nuavg demonstrates
monotonic behavior with the Ha and it augments when the strength of the non-uniform
magnetic field increases. The Nuavg improvement is in the
vicinity of 11.71% at Ha=10 and 23.26% at Ha=18 for Re=25. The maximum value of entropy
generation, SL when the non-uniform magnetic field is
applied. Moreover, increasing the Hartmann number, Ha influences the
high levels region of entropy production by relatively extending this zone
towards the downstream of the channel and covering more area around the cylinder.
According to the outcomes of numerical simulation, there is an increase in Nuavg
with 3.98% and 3.88% for Ha=2 and 18 respectively when the
ferrofluid volume fraction rises from Φ=0% to Φ=4% at Re=25.
Finally, the optimum thermal performance criterion, ξ is obtained at Re=150
for Ha=0 and Φ=4%.