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Preparation of nanofluids

In general, the preparation of nanofluids can
be divided into three parts: pH control,
addition of surfactants, and use of ultrasonic
vibration.

In this study, the nanofluids used were
supplied by DEGUSSA Company from
Germany (VP Disp. W740).The fluids have
TiO2 nanoparticles with average diameters
of 21 nm, suspended in water base fluid which
has concentration of 40 wt.%.

In the experiment, the nanofluids were diluted
by adding water to achieve the desired
concentration levels of 0.00005, 0.0001,
0.0005, 0.005, and 0.01 vol.%. After that, the
fluids were treated with ultrasonic vibration
for 2 h to distribute the nanoparticles evenly.
Fig. 1. TEM image of dispersed TiO2 nanoparticles in water.
Experimental apparatus
Fig. 2.Schematic diagram of experimental apparatus.
Table 1 Roughness of copper and aluminium heating surface.