ملخص البحث :

The laminar 2-D blended convection of the nanofluids at different volume fractions has gained interest in the last decade due to an enormous application in technology. The laminar-flow stream system can be further modified by changing the geometry of the channel, adding an external heating source, and changing the initial conditions at which the stream is being influenced. The investigation of this system includes the variation of the geometrical parameters of the channel, Reynolds number, Nusselt number, and type of the nanoparticles used in preparing the nanofluid with water as the base fluid. These parameters constitute a very successful leading to utilize the numerical solutions by using a finite volume method. Regarding heat flow, one side of the channel was supplied by the heat while the temperature of the other side was kept steadily. The upstream walls of the regressive confronting step were considered as adiabatic surfaces. The nanofluids were made by adding aluminum oxide (Al2O3), copper oxide (CuO), silicon dioxide (SiO2), or zinc oxide (ZnO) nanoparticles to various volume fractions in the scope of 1 to 4% and diverse nanoparticle diameters of 25 to 80 nm. The calculations were performed with heat flux, Reynolds numbers (Re), and step height (S) at a range of 100 < < 600 W/m2, 100 < Re < 500, and 3 ≤ S ≤ 5.8, respectively. The numerical study has shown that the nanofluid with SiO2 has the highest value of the Nusselt number (Nu). The distribution area and the Nu increase as Reynolds number increases and diminish as the volume fraction diminishes with the increase of the nanoparticle diameter. The outcome of this paper has shown that assisting flow has shown superiority over the opposing flow when Nu increases.