Laminar forced convective mass transfer of γ-Al2O3/electrolyte nanofluid in a circular tube

Mass transfer of ferricyanide ions through electrolyte nanofluids in a circular tube was investigated experimentally. Nanofluids consisted of 40 nm γ-Al2O3 nanoparticles suspended in ferri-ferrocyanide and aqueous sodium hydroxide as base fluid. Well known electrochemical limiting diffusion current technique was used to measure mass transfer coefficients. Measurements showed that mass transfer coefficient increased with concentration of nanofluid up to 0.01%. For greater concentrations of nanoparticles in nanofluid mass transfer coefficient decreased with the concentration. The augmentation of mass transfer coefficient for 0.01% nanofluid, was about 16.8% at Re = 1260 relative to the base liquid. Enhancement ratio which is defined as the ratio of the mass transfer coefficient of the nanofluid to the mass transfer coefficient of the base fluid slightly decreases with Reynolds number.

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► Mass transfer coefficient of nanofluids in a tube was measured experimentally.
► Mass transfer coefficient increased with the concentration of nanofluid up to 0.01%.
► The augmentation for 0.01% nanofluid was about 16.8% at Re = 1260.
► Mass transfer coefficients decreased in higher concentrations of nanoparticles.
► Enhancement ratio slightly decreased with Reynolds number.