Entropy generation and natural convection of nanofluids in a trapezoidal cavity having an innersolid cylinder

A numerical analysis of entropy generation and natural convection in a trapezoidal cavity with an internal solid cylinder filled with Al2O3 - water nanofluid has been investigated using finite difference method. The bottom wall is thermally insulated while the left and right walls were cooled isothermally. Remainder of these walls are kept adiabatic. Particular factors have been focused on the effects of Rayleigh number, dimensionless radius of the solid cylinder and nanoparticles of volume fraction on streamlines, isotherms, isentropic, local and average Nusselt number. Obtained results have demonstrated that the Rayleigh number and size of the solid cylinder are important control parameters for optimizing heat transfer and Bejan number.