Convective heat transfer characteristics of nanofluids including the magnetic effect on heat transfer enhancement - a review

Highlights: • Experimental and numerical investigations on the convective heat transfer of various nanofluids are summarized and discussed. • Convective heat transfer can be improved when small-sized nanoparticles was used. • Magnetic field in magnetic nanoparticles improves the convective heat transfer performance. The scope of this review enlightens the experimental and numerical investigations conducted on the convective heat transfer of various nanofluids, particularly hybrid nanofluids. Essential studies on the improvement of the convective heat transfer using suspensions of nanoparticles in traditional working fluids have recently appeared in the literature. Optimized heat and mass transfer of nanofluid are significantly affected by inherent nanofluid characteristics, synthesizing method for the nanofluid, the effect of magnetic force, concentration and size of nanoparticles, and Re (Reynolds number). Besides, a critical factor regarding the material properties, thermal properties, and performance of the magnetic nanofluids is highly sensitive to the small variation in the magnetic force and magnetic field gradient. Several studies have concluded that the magnetic field in magnetic nanoparticles improves the convective heat transfer performance of a nanofluid by approximately 13%–75%. Furthermore, some applications of a hybrid nanofluid in thermal systems have also been introduced.