The heat transfer performance of the conventional fluids
used in heat exchange processes improves by dispersing
nanoparticles with high thermal conductivity, as many
researches have shown in the last decades. The heat transfer
capability of a fluid depends on several physical properties
among which the rheological behavior is very relevant, as we
have previously pointed out.
In this study, different samples of nanofluids have been
analyzed by using a DHR-2 rotational rheometer of TA
Instruments with concentric cylinder geometry in the
temperature range from (278.15 to 323.15) K. The used base
fluids were two different binary mixtures of propylene glycol
and water at (10:90)% and (30:70)% mass ratios. Two different
mass concentrations (viz. 0.25 and 0.5 wt.%) of graphene
nanoplatelets functionalized with sulfonic acid (graphenit-
HW6) were dispersed in these two base fluids.
Firstly, with the goal of checking and calibrating the
operation of the rheometer, the viscosity-shear stress curves for
pure propylene glycol, Krytox GPL102 oil, and the two base
fluids were experimentally determined. A detailed comparative
study with those well-known data over the entire range of
temperature was stabilized obtaining deviations in viscosity less
than 3.5%. Then, the flow curves of the different nanofluid
samples were studied at different temperatures to characterize
their flow behavior.
Papers presented to the 12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Costa de Sol, Spain on 11-13 July 2016.