Computational analysis of comparative heat transfer enhancement in Ag-H2O, TiO2-H2O and Ag-TiO2-H2O: Finite difference scheme

Background: In recent years, researchers are mainly focused on the analysis of heat transfer enhancement due to its wide range applications in industries. In order to increase the heat transfer rate of base fluid, nano-particles and hybrid nano-particles are used and it is an attractive topic for research nowadays. This study focuses on the comparative analysis of heat transfer in flow of nanofluids (i.e. silver-water and titanium dioxide-water) and hybrid nanofluid (i.e. silver-titanium dioxide-water) over stretchable permeable sheets. Nanofluids saturated porous media, which is described by Darcy's law. Impacts of thermal radiation and viscous dissipation are accounted in the energy equation. Methods: The considered flow problem is formulated in the form of a coupled partial differential equations system. By appropriate dimensionless variables the PDE's system is transformed to dimensionless form. The obtained dimensionless PDE's system is solved computationally by the finite difference scheme. The obtained results are analysed through graphs and tables. The impacts of flow variables (i.e. Reynolds number, porosity parameter, nanoparticles shapes, nanoparticles fraction, suction/injection parameter, thermal radiation and Eckert number) on skin friction, velocity, Nusselt number and temperature are properly discussed. Significant findings: From the obtained results, concluded that velocity is dominant respectively in silver-water, titanium dioxide-water and silver-titanium dioxide-water. Temperature increases through Eckert number and decreases for thermal radiation. Temperature dominant respectively in titanium dioxide-water, silver-water and silver-titanium dioxide-water. In silver-water and titanium dioxide-water nanofluids the temperature is dominant respectively for spherical, brick, cylinder and platelet types nanoparticles while reversed order observed for silver-titanium dioxide-water hybrid nanofluid.