An investigation on flow and heat transfer due to mixed convection,
in a lid-driven rectangular cavity filled with Cu- water nanofluids and submitted to uniform heat flux along with its
vertical short sides, has been conducted numerically by solving the full
governing equations with the finite volume method and the SIMPLER algorithm. In
the case of a slender enclosure, these equations are considerably reduced by
using the parallel flow concept. Solutions, for the flow and temperature
fields, and the heat transfer rate, have been obtained depending on the
governing parameters, which are the Reynolds, the Richardson numbers and the solid volume
fraction of nanoparticles. A perfect agreement has been found between the
results of the two approaches for a wide range of the abovementioned
parameters. It has been shown that at low and high Richardson numbers, the convection is ensured
by lid and buoyancy-driven effects, respectively, whereas between these
extremes, both mechanisms compete. Moreover, the addition of Cu-nanoparticles, into the pure water,
has been seen enhancing and degrading heat transfer by lid and buoyancy-driven
effects, respectively.