SudarmadjiSudarmadjietal(1)carried out
convective heat transfer experiments With Al2 03 water nanofluids in the developing region of
Double pipe heat exchanger. In their work two particle sizes (20-50) nm
were used and it was observed that the Connective heat transfer increases
significantly higher than that of the pure water.
SUDARMADJI SUDARMADJIETAL(2)carried out the convective heat
transfer of
the Al2 03 - water nanofluids increases with increasing
both the Reynolds number and Volume
concentration.
ANOOPETAL (3) carried out convective heat transfer experiments with Al2 03 water
nanofluids in the developing region of pipe
flow with constant heat flux to evaluate the effect of
particle size on convective heat transfer co efficient. In their work two
particle sizes (45nm and 150 nm) were used and it was
observed that the nanofluid with 45nm particles showed
higher heat transfer co efficient than that with 150nm particles.
Choi (1995) is the first
researcher who worked on nano particles at the Argonne National Laboratory,
USA. He demonstrated that nanofluids exhibit an increased thermal conductivity
compared to the host fluid.
Eastmanetal. (1997)
observed that oxide nanoparticles, such as Al2O3 and CuO have excellent
dispersion properties in water, oil and ethylene glycol and form stable
suspensions.
Herisetal. (2007) conducted an
experimental study exclusively on Al2O3/water Nanofluid with nanopartcle
concentration from 0.2 to 2.5% volume fraction in the laminar flow condition
with constant wall temperature boundary condition and observed higher heat
transfer coefficients with the nanofluids. It was concluded that in addition to
increased thermal conductivity of nanoparticles, other parameters like
dispersion and chaotic movement of nanoparticles, Brownian motion, particle
migration, and particles interaction may augment heat transfer in the
Nanofluids. 2.5