Hydrothermal characteristics of a water-TiO2 nanofluid were evaluated numerically
within annuli considering the effects of particle migration. The convective
heat transfer coefficients increased at both inner and outer walls of the annulus
by raising the concentration. Along the annulus, the friction coefficient decreased
more rapidly at lower Reynolds numbers. Taking the particle migration into
account, a nonuniform concentration distribution was observed at the annulus
cross section, higher heat transfer coefficients were obtained at both walls, and
the velocity profile became flatter. In addition, the influence of thermophoresis
on the convective heat transfer proved to be more significant than that of
Brownian diffusion.
