Affiliations: [a] Department of Mechanical Engineering, School of
Energy, Kermanshah University of Technology, Kermanshah, Iran | [b] School of Mechanical Engineering, Iran University of
Science and Technology, Narmak, Tehran, Iran
Correspondence:
[*]
Corresponding author: Mehdi Bahiraei, Department of Mechanical
Engineering, School of Energy, Kermanshah University of Technology, Kermanshah,
Iran. E-mail: bahira@iust.ac.ir
Abstract: This study has used the two-phase Euler-Lagrange method to evaluate
the hydrothermal characteristics for a laminar flow of
water-Mn_{0.6}Zn_{0.4}<FORMULA>Fe<FORMULA>_{2}O_{4} magnetic nanofluid
in a circular pipe under the effect of magnetic field with both positive and
negative gradients. Brownian and thermophoretic forces were considered in the
simulation. Concentration distribution was found to be non-uniform at the cross
section of the pipe, the value of which is greater in center of the pipe than
near wall. Non-uniformity in the concentration distribution will change the
velocity profile under the application of magnetic field. Applying magnetic
field with negative gradient increases the convective heat transfer
coefficient, while decreases it in the case of positive gradient. Increasing
the magnitude of magnetic field gradient causes a more considerable change in
the convective heat transfer coefficient. In the presence of the magnetic
field, the convective heat transfer coefficient also increases with increasing
Reynolds number, concentration and particle size which the effects of magnetic
field on heat transfer is less significant at higher Reynolds numbers.
Moreover, the pressure drop increases in the case of applying magnetic field
with negative gradient while applying the positive one would act as a pump and
sucks the fluid from upstream.
Keywords: Heat transfer, nanofluid, Mn-Zn ferrite, Euler-Lagrange, magnetic field
