Abstract:
An elaborate numerical study of developing a model regarding conjugate effect of fluid
flow and heat transfer in a heat conducting vertical walled cavity filled with copper-water
nanofluid has been presented in this thesis. This model is mainly adopted for a cooling of
electronic device and to control the fluid flow and heat transfer mechanism in an
enclosure. The numerical results have been provided in graphical form showing effect of
various relevant non-dimensional parameters. The relevant governing equations have been
solved by using finite element method of Galerkin weighted residual approach. The
analysis uses a two dimensional rectangular enclosure under conjugate convective
conductive heat transfer conditions. The enclosure exposed to a constant and uniform heat
flux at the left vertical thick wall generating a natural convection flow. The thicknesses of
the remaining parts of the walls are assumed to be zero. The right wall is kept at a low
constant temperature, while the horizontal walls are assumed to be adiabatic. A moveable
divider is attached at the bottom wall of the cavity. The governing equations are derived
for the conceptual model in the Cartesian coordinate system.
Firstly, conjugate heat transfer in a rectangular enclosure filled with nanofluid is
numerically investigated. Study have been carried out for the solid volume fraction
0 ≤ 𝜙 ≤ 0.05. The effects of Rayleigh number, the value of convective heat transfer
coefficient, location of the divider position, the solid fluid thermal conductivity ratio and
thickness of solid wall on the hydrodynamic and thermal characteristic of flow have been
analyzed. Results are presented in the form of streamlines, isotherms and average Nusselt
number. An increase in the average Nusselt number was found with the solid
concentration for the whole range of Rayleigh number. In addition, the obtained results
show a considerable effect on the heat transfer enhancement. In particular it is interesting
to mention that divider can be located inside the partition to control heat transfer
especially in electronic device.
Secondly, the numerical solution will also be carried out for the problem of MHD
conjugate natural convection flow in a rectangular enclosure filled with electrically
conducting fluid. The effect of Hartmann number on the pertinent parameters on the flow
and temperature fields and heat transfer performance of the enclosure will also be
examined. It is expected that the heat transfer rate will increase with an increase of
Rayleigh number, divider position and solid fluid thermal conductivity ratio, but it should
viii
decrease with an increase of the Hartmann number. It is also expected that an increase of
the solid volume fraction will enhance the heat transfer performance.
