Improving Heat Transfer Efficiency in Shell-and-Tube Heat Exchangers through the Incorporation of Alkaline Water Nanofluids

This investigation aimed to experimentally assess the operational efficiency of a shell-and-tube heat
exchanger utilizing nanofluids containing Magnesium oxide nanoparticles and alkaline water
(MgO-AW), as well as Manganese dioxide and alkaline water (MnO2-AW). The nanofluids,
comprising unsurface-modified MgO-AW and MnO2-AW nanoparticles, underwent synthesis. The study involved analyses to evaluate the impact of varied volume concentrations of nanoparticles on
crucial parameters such as thermal conductivity, viscosity, heat transfer coefficient, friction factor,
Nusselt number, and pressure drop. The distinctive inherent properties of the nanoparticles resulted
in the observation that introducing MgO and MnO2 nanoparticles at a concentration of 0.1 weight
percent led to a 29% and 39% increase in the thermal conductivity of the nanofluids, respectively,
as indicated by the experimental findings. Moreover, the convective heat transfer coefficient
experienced enhancement due to the improved thermal conductivity of the two-phase mixture.
Additionally, the friction factor exhibited an increase due to simultaneous rises in both the viscosity
and density of the nanofluids. Furthermore, when comparing the MgO nanofluid with the MnO2
nanofluid, it was noted that the latter displayed a significantly reduced pressure drop. This
phenomenon can be attributed to the augmentation of the thermophysical properties of the
nanofluid.