A numerical investigation is carried out to assess the effect of magnetic field on the entropy generation
characteristics of a magnetic nanofluid flowing between parallel plates using the two-phase mixture model.
The magnetic field is generated by one or multiple line dipole(s). The influences of Reynolds number,
magnetic field strength, number of dipoles and also their arrangement are examined on the thermal, frictional
and total entropy generation rates both locally and globally. The application of a magnetic field leads to rotation
of magnetic nanofluid and consequently, mixing in the flow and more uniform temperature distribution.
The results show that augmenting the magnetic field strength from 0.01 Am to 0.1 Am, at Reynolds number of
500, results in a 2.93% increase and a 5.54% decrease in the global frictional and thermal entropy generation
rates, respectively. Moreover, it is reported that increasing the Reynolds number from 500 to 2000, for a magnetic
field with strength of 0.1 Am, causes an increase of 63.02% and a decrease of 50.45% in the global frictional
and thermal entropy generation rates, respectively. In the case of one dipole, the results reveal that
the position of the dipole has no effect on the global total entropy generation rate, but this is not true for
two and three dipoles cases.