  This article represents a set of results numerically studied in the framework
of laminar double diffusive natural convection. We have investigated the
thermophysical comportment of Water-based incompressible nanofluids
circulating, due to buoyancy forces, inside a two-dimensional enclosed
rectangular cavity for two comparable cases of considering or not a centered
isothermal block. Results of this investigation are mainly built on parametric
study of the most analytical variables that govern the flow. The buoyancy ratio
ranged from -5 to 100, while Rayleigh number ranged from 103 to 106, and Lewis
number ranged from 0 to 200. Four types of nanoparticles were considered:
Copper, Alumina, Carbon-nanotubes and Titania which had a concentration range
from 0 to 0.1.The flow is characterized by the isotherms, isoconcentrations and
streamlines, and results were discussed in term of Nusselt and Sherwood average
numbers, Streamlines maximum average values and Kinetic energy as function to
the various aforementioned governing parameters.
