Today, a large part of the energy required in industry and also for domestic use is
in the form of thermal energy. For this reason, researchers have always sought to
improve or develop new ways to increase the rate of heat transfer in thermal
systems. As a result of these efforts, their efficiency has increased and economic
costs have decreased in most cases. In recent years, viscous fluid flow and forced
convection heat transfer from the cylinder has been the focus of many researchers
due to its wide application in heat exchangers. Many methods are used to improve
the performance of these devices, leading to energy savings, reduction of system
size and heat transfer time. Among these methods, we can mention the use of
nanofluids and porous materials, which are passive methods of increasing heat
transfer. In this regard, this thesis first numerically investigates the flow of
nanofluid and heat transfer around and inside a full porous cylinder and a cylinder
with a porous coating, taking into account the relative velocity between the base
fluid and the nanoparticle and the equality of the temperature of the solid phase
and the nanofluid of the porous medium using Fluent software pays. For this
purpose, mixture two-phase method for nanofluid modeling and Darcy-BrinkmanForchheimer model and one-equation energy model have been used for modeling
flow and heat in porous media. In the second part of the thesis, the hydrodynamic
and thermal investigation of the cross-flow of nanofluid from a cylinder with a
porous coating, assuming no slippage of the base fluid and nanoparticle, and the
temperature inequality of the solid phase and the nanofluid of the porous
medium, has been discussed using Comsol software. The results showed that the
increase of Darcy number, Reynolds number and volume fraction increases the
heat transfer from the porous cylinder and the effect of Darcy number on heat
increase is greater than that of volume fraction. Increasing the Reynolds number
and the