Thermal stability analysis of laminar nanofluids free convection in horizontal cylinder

Abstract EN

The effect of nanoparticles on the heat transfer of the fluids becomes one of the most interesting fields for researches.

Metallic and nonmetallic materials are used to enhance the thermal performance of the fluids.

In this work, an attempt was made to extend the work in this field to study the effect of addition of copper oxide nanoparticles on the transient behavior of free convection in horizontal cylinder.

The dimensionless form of the energy and the momentum equations was solved using the commercial package COMSOL 3.5.

A constant wall temperature CWT boundary condition was subjected to the surfaces of the cylinder.

The lower half of the walls temperature was always higher than the upper one.

The effect of volume fraction of nanoparticles on the stability of the transient behavior of the heat transfer and the fluid flow was examined.

Also the effect of Rayleigh number on the velocities, temperature and Nusselt number are shown graphically.

It is found that not only the onset of instability of the natural convection but also the type of the steady state profiles of temperature and velocities were affected by the existence of the nanoparticles.

A phase plane plot was used to analysis the steady state types of dynamic behavior of the nanofluid natural convection under the CWT boundary condition.