Numerical Analysis of mixed conviction heat transfer for different nanofluids inside concentric annulus

In this study, numerical mixed convection heat transfer in a horizontal concentric annulus in the presence of water-based fluid with nanoparticles of aluminum oxide, copper, silver and titanium dioxide discussed. Numerical solution using finite volume method based on SIMPLE algorithm is done and discretization of equations generally is first order. Inner and outer cylinders have constant temperature and inner cylinder temperature is higher than outer one. Both of the cylinders can be rotated in either direction with constant angular velocity. The effect of parameters such as Rayleigh, Richardson, Reynolds number and volume fraction of nanoparticles on heat transfer and flow pattern discussed. Results showed that by increasing Rayleigh number increases heat transfer, heat transfer rate also increases with increasing volume fraction of nanoparticles and these increase is about 8.25 percent for 5 percent nanoparticles by volume. Rotation of cylinders reduces the overall heat transfer rate. Different rotation has large impact on the flow pattern and heat transfer. Adding nanoparticles has not significant impact on the flow patterns and isotherms but is effective in quantity. The results has good agreement with the similar work has been done before.