In this experimental study heat transfer and pressure drop behavior of
ZnO/water nanofluid flow inside a circular tube with constant wall
temperature condition is investigated where the volume fractions of
nanoparticles in the base fluid are 1% and 2%. The experiments? Reynolds
numbers ranged roughly from 5000 to 30000. The experimental measurements
have been carried out in the fully-developed turbulent regime. The results
indicated that heat transfer coefficient increases by 11% and 18% with
increasing volume fractions of nanoparticles respectively to 1% and 2% vol.
The measurements also showed that the pressure drop of nanofluids were
respectively 45% and145% higher than that of the base fluid for volume
fractions of 1% and 2% of nanoparticles. However experimental results
revealed that overall thermal performance of nanofluid is higher than that
of pure water by up to 16% for 2% vol. nanofluid. Also experimental results
proved that existing correlations can accurately estimate nanofluids
convective heat transfer coefficient and friction factor in turbulent
regime, provided that thermal conductivity, heat capacity, and viscosity of
the nanofluids are used in calculating the Reynolds, Prandtl, and Nusselt
numbers.