Numerical investigation of porosity effect on confined round impinging jets of nanofluids in aluminum foams

In this paper a numerical study on mixed convection in confined impinging round jets in a porous media is carried out. Pure water and Al2O3/water based nanofluids are employed as working fluids; a single-phase model approach has been applied to evaluate their properties. A two-dimensional domain is analyzed and different Peclet are considered. The Rayleigh number is fixed equal to 30000. The thermal non-equilibrium energy condition (LTNE) is assumed to accomplish two-dimensional simulations on the metal foam section. The examined aluminum foams are characterized by distinct porosity from 0.90 to about 0.97, for different values of pores per inch (PPI), equal to 5, 10, 20 and 40. The particle volume concentrations range from 0% to 4% and the particle diameter is equal to 30 nm. The target surface is heated by a constant temperature value, calculated according to the value of Rayleigh number. The results show that the convective heat transfer coefficients increase with increasing of values of Peclet number and nanoparticle concentration. Furthermore, the heat transfer coefficient shows a different behavior at varying porosity for different Peclet and Rayleigh numbers. In addition, temperature profiles are presented for the fluid and solid phases of the porous zone.