Effects of paralleled magnetic field on thermo-hydraulic performances of Fe3O4-water nanofluids in a circular tube

Thermal and exergy efficiency of magnetohydrodynamic Fe3O4‐H2O nanofluids flowing through a built‐in twisted turbulator corrugated tube under magnetic field

“…The sample nanofluids can be stored for 10 days without obvious sedimentation (see Figure 2). It has been learned from the foregoing 47 that when the mass fraction of nanoparticles exceeds 1%, continuing to increase the mass fraction does not enhance the heat transfer capacity of the working fluids as expected. This not only adversely affects the stability of the nanofluids but also wastes resources.…”

“…In the previous work, 47 the reason for adopting Fe 3 O 4 ‐H 2 O nanofluids as a working medium has already been introduced: favorable magnetic effect, simple preparation process, as well as good fluid stability. Therefore, it is reasonable to select this sample as the heat transfer medium.…”

“…Finally, the samples are vibrated for 2 h by the ultrasonic vibrator, whereas the pH is adjusted to 8.0. Mei et al 47 have given the basis for the selection of some parameters in the preparation process and analyzed the stability of sample nanofluids. The sample nanofluids can be stored for 10 days without obvious sedimentation (see Figure 2).…”

“…Naphon et al researched the nanofluids heat exchange enhancement mechanism in the micro‐channel heat sink 39 and micro‐fin tubes 40 by experimental research and numerical simulation, and made corresponding progress. Qi et al conducted detailed studies on the forced convection heat transfer of different nanofluids, such as SiO 2 ‐H 2 O nanofluids in the triangle tube, 41 water‐based TiO 2 nanofluids in double‐pipe heat exchangers, 42 in triangular tubes, 43 in CPU cooling system 44,45 and in different helical tubes, 46 Fe 3 O 4 ‐H 2 O magnetofluids in the circular tube under vertical magnetic field 47 . These studies all reflected that nanofluids have better heat transfer characteristics and comprehensive performance in comparison with the based fluid.…”

Experimental study on thermo‐hydraulic performance of nanofluids upward flowing through helical tubes of heat exchanger system based on thermal efficiency

“…Recently, for the sake of improving the heat transfer efficiencies of current exchangers, many unusual enhanced tubes have been selected to achieve enhanced heat transfer, such as spirally coiled tube with magnetic field, helically corrugated tube, inlet swirl generator, horizontal elliptical tube, helical pipe, circular tube filled with nanoliquid–metal fluid, circular tube with rotating twisted tape, circular duct with helical turbulators, built‐in–twisted tape triangular tube, porous media in exchanger, corrugated tube under magnetic field, square duct equipped with transverse twisted baffles, and circular tube under paralleled magnetic field . Besides, porous media, as an enhanced heat transfer technology, have been studied by many researchers .…”