Entropy Generation Analysis of Spherical and Non-Spherical Ag-Water Nanofluids in a Porous Medium with Magnetic and Porous Dissipation

The analysis of the entropy generation in spherical and non-spherical Ag-water nanofluids flow and heat transfer over a stretching cylinder is carried out in the presence of a viscous dissipation, magnetic field and porous medium. The Hamilton-Crosser nanofluid model for effective thermal conductivity is used to calculate the velocity and temperature profile. The modeled governing partial differential equations are transformed by a similarity transformation into self-similar ordinary differential equations and are solved numerically using the shooting method. The numerical solutions obtained for the velocity and temperature profile are used to calculate entropy generation number. Finally, changes in velocity, temperature, entropy generation number with physical flow parameters are presented graphically and discussed physically in detail. The results show that the entropy generation in the boundary layer flow of nanofluid-containing spherical nanoparticles is lower. It is also found that the flat stretching sheet causes less entropy generation compared to stretching cylinder.