A study of heat transfer rate of spherical copper and alumina nanoparticles in water and ethylene glycol based fluids was carried out. A modified thermal conductivity model in conjunction with steady state momentum and energy equations in spherical coordinates were put into dimensionless form and solutions used to determine the skin friction, heat transfer coefficient and thermal conductivity as well as viscosity. The modified model incorporates Brownian motion and varied sphericity to observe the effect of temperature and other material parameters on the velocity and temperature profiles of the fluid. Using numerical values, it was shown that the nanoparticle volume fractions, the diameter and Prandtl number, not only enhanced the thermal conductivity of nanofluids but also the velocity and temperature profiles. It was also observed that the Brownian motion which is temperature dependent was actually a weak factor in enhancement of thermal conductivity. The effect of other parameters as well as calculation of mass flux and mean temperature was determined.
Financed by the National Centre for Research and Development under grant No. SP/I/1/77065/10 by the strategic scientific research and experimental development program:
SYNAT - “Interdisciplinary System for Interactive Scientific and Scientific-Technical Information”.